Class 11 Medical Biology - Breathing And Exchange Of Gases

Mention a cause and symptom of each of the following.
(i) Emphysema
(ii) Renal calculi
(iii) Diarrhoea

(i) Emphysema is a form of chronic lung disease which is caused by smoking. The symptom is shortness of breath.

(ii) Renal calculi also known as kidney stone is caused due to the presence of more crystal forming substances such as calcium, oxalate and uric acid in the urine. The symptoms include blood in the urine and pain in the abdomen or groin.

(iii) Diarrhoea is caused by the infection with bacteria, viruses and parasites. The symptoms include watery stool, vomiting and dehydration.

Draw a neat labelled diagram of lungs in man.

The diagram represents the structure and parts of lungs in humans.

What is the role of epiglottis and diaphragm in respiration?

The epiglottis is the flap-like structure. This is the covering above the trachea which prevents the entry of food in the respiratory system. This flap opens when the air is taken in and given out. This allows the air to move in and out of the tracheal system.
The diaphragm is the membranous structure in the abdomen. This structure becomes flat during inspiration which helps to increase the volume of the thoracic cage. This allows the air to be taken in the lungs. During the process of expiration, the diaphragm becomes dome-shaped. This reduces the volume of the thoracic cage and helps to pump the CO$$_2$$ out from the lungs.

With regard to the respiratory system and the process of respiration in man, answer the following questions:
Name the two muscles that help in breathing.

The intercostal muscles(internal and external) and the diaphragm help in a change in volume of the thoracic cavity and help in breathing. Both the diaphragm and intercostal muscles contract to allow the inhalation. During the exhalation, the external intercostal muscles contract and the diaphragm relax to allow the outward movement of gases.
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How are the human lungs best designed for the terrestrial mode of respiration?

The anatomical set up of lungs in thorax is such that any change in the volume of the thoracic cavity will reflected in the lung cavity from which we can not directly alter the pulmonary volume as well as it helps in diffusing the maximum amount of oxygen by increasing the surface area with the help of alveoli which fulfill the needs of oxygen requirement by human and it also expand to fill the maximum amount of air. In this way, the human lungs are the best design for the terrestrial environment.

Describe how the ventilation of the lungs will change while the athlete exercise:

When the air is expelled, the volume of the lung decreases as air is forced out of the lungs. With every breath, air is moved into the lungs and oxygen and carbon dioxide are exchanged. During exercise, muscles work harder and body uses more oxygen and produces more carbon dioxide. During exercise the demand for oxygen increases because oxygen is needed to burn calories more efficiently. Since the blood picks up oxygen in the lungs, and the demand for oxygen increases so the lungs must work harder. With a faster breathing rate, more oxygen is picked up at the lungs for delivery to the working muscles.

What are the functions of:
Larynx, trachea, bronchi and lungs in humans?

The functions of the following organs are:

1. Larynx - It is known as the voice box and is responsible for the production of sound waves that helps in communication.

3. Trachea - It is the windpipe which helps in taking the air to the lungs.

3. Bronchi - They are the main passage to take and distribute the air into the lungs.

4. Lungs - The lungs provide a platform for the exchange of gases in the body and the blood.

Name the structure that control breathing?

The medulla oblongata is the primary respiratory control center. Its main function is to send signals to the muscles that control respiration to cause breathing to occur. There are two regions in the medulla that control respiration: The ventral respiratory group stimulates expiratory movements. The dorsal respiratory group controls mostly inspiratory movements and their timing.

Using what you know about particle theory,explain how oxygen diffuses from an air sac into the blood.

Diffusion of oxygen into the blood takes place at the alveoli (air sacs). The alveoli are very close to capillaries, which are small blood vessels. The blood in the capillaries has very little oxygen and has a lot of carbon dioxide.
The walls of both the alveoli and the capillaries are very thin and oxygen and carbon dioxide move along the concentration gradient. This movement is called diffusion.
Oxygen diffuses from the alveoli, into the blood in the capillaries. Similarly, carbon dioxide from the blood moves out of the capillaries into the alveoli.

Maximum amount of oxygen is lost from the blood in the?

Capillaries are blood vessels with very thin walls.
These thin walls enable a higher diffusion of gases from the capillaries as compared to that from arteries and veins.
The capillaries surrounding tissues enable the maximum exchange of gases between them and the tissues.

What is the role of epiglottis in respiration ?

The epiglottis is a leaf-like or flap-like tissue which seals off the trachea while swallowing food so as to prevent the entry of food in windpipe or trachea, but at the time of respiration, it remains open.

How do alveoli help in gas exchange?

Alveoli are site of gas exchange. They are tiny sac-like air chambers at the end of each bronchial inside the lungs. Alveoli are thin walled structure that are surrounded by a network of small blood vessels where the exchange of gases between lungs and blood occurs. The inhaled oxygen present inside the alveoli of lungs goes to blood in the capillaries. The blood in turn passes the carbon dioxide to the alveoli of lungs.

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
C-shaped cartilage rings and .........

The c-shaped cartilaginous rings in the respiratory tracts prevent the collapse of the respiratory tract. So, the correct statement is 'C shaped cartilaginous rings and prevention of collapse of the trachea'.

State one function of pleural fluid.

The pleural cavity present between the pleural membranes around the lungs contains pleural fluid, which acts as a lubricant and allows the pleurae to slide effortlessly against each other during respiratory movements.

How is the respiratory passage kept free of dust particles?

Hair is present in the nasal passage (nose) that help remove dust particles. Besides this the constant motion of cilia and mucous present in the walls of the respiratory tract also help trap dust particles, pollen and fine microorganisms. In this way the respiratory tract is kept free of dust particles.

STRUCTURED/APPLICATION/SKILL TYPE
Given alongside is a diagrammatic sketch of a kind of part in human lungs :
What do the arrows 5 & 6 indicates ?

5- indicates breaking of carboxyhaemoglobin to give out carbon dioxide in the alveolar space.

6-Indicates combing of oxygen with the haemoglobin of RBC and forming oxyhaemoglobin.

Give suitable explanations for the following:
Why does gaseous exchange continue in the lungs even during expiration?

Even after exhalation, a small volume of air (about 1200ml ) remains in the lungs. This is called the residual volume of air and it circulates through the alveolar capillaries, thus helping in the gaseous exchange of air even during expiration.

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
Alveoli and .........

Alveoli is associated with the exchange of gases through its thin wall made of a single layer of squamous epithelium.

The correct statement is 'Alveoli and exchange of gases'.

VERY SHORT ANSWER TYPE
Match the items in Column I with the ones most appropriate in Column II. Rewrite the matching pairs:
Column I column II
(a) Alveoli (i) where aerobic respiration takes place
(b) Bronchioles (ii) lined with hair
(c) Nasal chamber (iii) diffusion of gases
(d) Bronchi (iv) small air tubes
(v) An inverted Y-shaped tube
(vi) A common passage for food and air

(a) Alveoli - (iii) diffusion of gases

(b) Bronchioles - (iv) small air tubes

(d) Bronchi - (v) an inverted Y-shaped tube

STRUCTURED/APPLICATION/SKILL TYPE
Given alongside is a diagrammatic sketch of a kind of part in human lungs :
Name the parts numbered 1-4.

1- Squamous epithelium of blood capillary

2-Red blood cells or Erythrocytes

3-Blood in the capillary lumen

4-Thin wall of the alveolus.

Mention any two occupational respiratory disorders and their causes in human beings ?

Occupational lung diseases are occupational, or work-related, lung conditions that have been caused or made worse by the materials a person is exposed to within the workplace.

It includes a broad group of diseases, including occupational asthma, chronic obstructive pulmonary disease (COPD), bronchiolitis obliterans, inhalation injury, interstitial lung diseases (such as pneumoconiosis, hypersensitivity pneumonitis, lung fibrosis), infections, lung cancer and mesothelioma.

These diseases can be caused directly or due to an immunological response to an exposure to a variety of dust, chemicals, proteins or organisms.

Write a note on the membranous covering of the lungs?

The lungs are situated within the thoracic cavity of the chest. Each lung is enclosed within a pleural sack which allows the inner and outer walls to slide over each other while breathing takes place, without much friction. The superficial layer lines the wall of the thoracic cavity and is called the parietal pleura, deep layer, the visceral pleura cover the lungs themselves.

The mucus in trachea is produced by which part?

The mucous in the trachea is produced by specialized epithelial cells.

Explain the mechanism of inspiration?

Inspiration is a part of breathing where the air is inhaled into the body. This involves :

1. The diaphragm pulls downwards.

2. The muscles of the ribs contract and move upwards.

3. The size of the thoracic cavity increases to allow more air.

4. Air is pulled inside through the nose.

5. The lungs inflate.

Name the process of inhalation and exhalation of air.

Breathing is the process of inhalation and exhalation of air.

Inhalation and exhalation are the processes by which the body brings in oxygen and expels carbon dioxide.

Breathing is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly by bringing in oxygen and flushing out carbon dioxide.

Why do the walls of trachea not collapse when there is less air in it?

In trachea , there are C shaped rings of cartilage which helps to hold them even when the air is less in it . Hence they do not collapse.

What is the role of mouth in respiration?

Mouth plays a secondary role in respiration and facilitates breathing in case the nasal passage is obstructed for some reason.

Write the names of inspiratory muscles.

External and Internal intercostal muscles are inspiratory muscles.

How are lungs designed in human beings to maximise the area for exchange of gases ?

Answer:

Each lung has a highly branched respiratory tract called a respiratory tree.
A primary bronchus divides into secondary bronchi, secondary into segmental bronchi, segmental bronchus into bronchioles which divides into terminal bronchioles, respiratory bronchioles, alveolar sacs and alveoli.
The alveoli are thin-walled and richly supplied with a network of blood vessels to facilitate the exchange of gases between blood and the air-filled in alveoli.
These alveoli have a balloon-like structure that provides maximum surface area for the exchange of gases.

Distinguish between inspiratory capacity and expiratory capacity.

	Inspiratory capacity (IC)	Expiratory capacity (EC)
1	It is the volume of air that can be inhaled after a normal expiration.	It is the volume of air that can be exhaled after a normal inspiration.
2	It includes tidal volume and inspiratory reserve volume.	It includes tidal volume and expiratory reserve volume.
3	IC = TV + IRV	EC = TV + ERV

What will be the $$pO_2$$ and $$pCO_2$$ in the atmospheric air compared to those in the alveolar air?
(i) $$pO_2$$ lesser, $$pCO_2$$ higher
(ii) $$pO_2$$higher, $$pCO_2$$ lesser
(iii) $$pO_2$$higher, $$pCO_2$$ higher
(iv) $$pO_2$$ lesser, $$pCO_2$$ leser

$$pO_2$$ higher will be higher and $$pCO_2$$ will be lesser in the atmospheric air as compared to those in the alveolar air.

The partial pressure of oxygen in atmospheric air is higher than that of oxygen in alveolar air. In atmospheric air, $$pO_2$$ is about 159 mm Hg. In alveolar air, it is about 104 mm Hg.

The partial pressure of carbon dioxide in atmospheric air is lesser than that of carbon dioxide in alveolar air. In atmospheric air, $$pCO_2$$ is about 0.3 mm Hg. In alveolar air, it is about 40 mm Hg.

Distinguish between vital capacity and total lung capacity.

	Vital capacity (VC)	Total lung capacity (TLC)
1.	It is the maximum volume of air that can be exhaled after a maximum inspiration. It includes IC and ERV.	It is the volume of air in the lungs after maximum inspiration. It includes IC, ERV, and residual volume.
2	It is about 4000 mL in the human lungs.	It is about 5000 – 6000 mL in the human lungs.

How is respiration regulated?

The respiratory rhythm centre present in the medulla region of the brain is primarily responsible for the regulation of respiration. The pneumotaxic centre can alter the function performed by the respiratory rhythm centre by signalling to reduce the inspiration rate.

The chemosensitive region present near the respiratory centre is sensitive to carbon dioxide and hydrogen ions. This region then signals to change the rate of expiration for eliminating the compounds.

The receptors present in the carotid artery and aorta detect the levels of carbon dioxide and hydrogen ions in the blood. As the level of carbon dioxide increases, the respiratory centre sends nerve impulses for the necessary changes.

Distinguish between
(a) IRV and ERV
(b) Inspiratory capacity and Expiratory capacity
(c) Vital capacity and total lung capacity

$$\textbf{Option (A)}$$

On the basis of	IRV	ERV
Definition	It is the extra volume of air a person can inspire forcefully beyond normal tidal volume.	It is the extra volume of air that can be breathed out beyond the normal tidal volume.
Volume	It is about 2500-3000 mL.	It is about 1000-1100 mL.

$$\textbf{Option (B)}$$

On the basis of	Inspiratory capacity	Expiratory capacity
Definition	It is the volume of air that can be inhaled forcefully after a normal expiration.	It is the volume of air that can be exhaled forcefully after a normal inspiration.
Total volume	It is the sum total of tidal volume and inspiratory reserve volume.	It is the sum total of tidal volume and expiratory reserve volume.

$$\textbf{Option (C)}$$

On the basis of	Vital capacity	Total lung capacity
Definition	It is the amount of air which can be maximum inspired and also maximum expired.	It is the total amount of air present in the lungs and the respiratory passage after a maximum inspiration.
Combination of capacity	It is the sum of tidal volume,inspiratory reserve volume and expiratory reserve volume.	It is the sum of the vital capacity and residual volume.
Volume	It varies from 3400 to 4800 ml.	It varies from 5000 to 6000 mL.

How are the alveoli designed to maximise the exchange of gases?

Alveoli are pouch-like air sac that is made up of simple squamous epithelium. It has a thin cell wall to facilitate gaseous exchange.
The presence of millions of alveoli in the lungs provides ample surface area to facilitate gaseous exchange between the air in alveoli and blood in surrounding capillaries.
Oxygen diffuses across the alveolar and capillary wall into the bloodstream while carbon dioxide diffuses from blood across the mentioned walls into the alveoli.

Air leaves the tiny sacs in the lungs to pass into capillaries. What modification is needed in the statement?

$$\bullet$$ The modification needed in the above statement is as follows: "Oxygen leaves the tiny sacs in the lungs to pass into capillaries."
$$\bullet$$ This modification in sentence is because it is not the air that leaves the tiny sacs in the lungs to pass into capillaries but it is the oxygen that leaves the tiny sacs in the lungs to pass into capillaries.

$$\textbf{Additional Information:}$$
$$\bullet$$ In the lungs, there are millions of tiny sacs called alveoli. The alveoli are surrounded by blood capillaries.

$$\bullet$$ Oxygen from the alveoli diffuses into the surrounding blood capillaries and carbon dioxide diffuses from the blood capillaries into the alveoli.

$$\bullet$$ Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.

State the difference between the two. Nasal cavity and ear canal.

Nasal cavity	Ear canal
It helps in smelling.	It helps in hearing.
It acts as a barrier for dust particles.	It also helps in balancing.

Why is the air entering the lungs dust free?

The air which is taken during breathing enters through the nostrils. The nostrils are lined with hair cells. These hairs capture and traps the dust particles. There are mucus secreting cells in these regions. The mucus helps to trap the bacteria and other microbes. This air passes through the tracheal tubes and then enters into lungs. The air which enters the lungs is dust free because all the microbes and dust particles are removed.

(a) Draw a labelled diagram of human respiratory system.
(b) Explain the transportation of oxygen and carbon dioxide in human beings.

Exchange of gases takes place between the alveoli of lungs and the surrounding blood capillaries. The two main gases exchanged are oxygen and carbon-dioxide. Oxygen is absorbed by the blood capillaries from the lungs alveoli by diffusion while carbon dioxide is absorbed by the lungs alveoli from blood capillaries by diffusion. Transport of oxygen and carbon dioxide occurs with the help of respiratory pigment called hemoglobin. Haemoglobin, the iron-containing respiratory pigment is a red coloured pigment of blood, which has a very high affinity for oxygen. Haemoglobin though is purple coloured but oxyhemoglobin is of bright red colour. Oxygen is transported from lungs to the body cells in the form of oxyhemoglobin. Carbon dioxide is transported from the body cell to the lungs in the forms of carboxyhemoglobin, carbonic acid, bicarbonates of sodium and potassium.

Explain how gaseous exchange takes place at alveoli and explain the regulation of respiration by brain.

Exchange of gases in the alveoli:

Once air is within the lungs the process of gaseous exchange begins. Capillaries of the pulmonary artery remain closer to the wall of the alveoli. This enhances the exchange of gases. Oxygen and carbon dioxide are exchanged across the alveolar member by diffusion from the site of higher to lower partial pressure until the partial pressure of the two regions is equal. This process is a simple physical one, which does not involve any secretory or active transport mechanism.

In atmospheric air, there is a high concentration of oxygen (20-25%) whereas the proportion of carbon dioxide if low (0.04%). The alveolar PO$$_2$$ is about 100 mm Hg and PO$$_2$$ of venous blood is about 40 mm Hg. This pressure gradient is sufficient for the transfer of O$$_2$$. The PCO$$_2$$ of venous blood is 46 mm Hg and that of alveolar air is only 6 mm Hg (1/10th of O$$_2$$), it is adequate for CO$$_2$$ transfer by diffusion.

Regulation of respiration:

In the brain, the medulla oblongata contains a respiratory center. This controls breathing. The respiratory center consists of an inspiratory center and an expiratory center. Axons from the nerve cells of these centers lead to the intercostal muscles through the intercostal nerves and the diaphragm via the phrenic nerves. These nerve fibres transmit impulses to the external intercostal and internal intercostal muscles alternately. The walls of the alveoli have sense endings, which are stimulated by changes in the tension of alveolar walls.
When alveoli are stretched at the height of inspiration the receptors send stimuli to the expiratory center of the medulla through the vagus nerve which inhibits further inspiration. This sequence of events is called Herring-Bruer reflex. In addition, the medulla contains a pneumotaxic center, which s connected to the breathing center and helps to ensure rhythmic breathing. During inspiration, the inspiratory part of the respiratory center sends impulses to the pneumotaxic center, which responds by sending impulses to the expiratory part of the respiratory center. The expiratory center is then activated and so the inspiratory center is inhibited reflexly. Thus the respiratory rhythm is controlled by these centers in the brain.

Write the name of four respiratory disorders with symptoms.

The four respiratory disorders are as follows :-

(1) Asthma: It is a type of allergic reaction in which mucous of respiratory canal becomes dense and thus expiration is affected. This disease is generally caused due to pollen grains of flowers and some food substances.
(2) Common cold: It is a viral disease in which swelling occurs in mucous membrane and secretion of mucous is also increased. The nose is blocked thus intake of oxygen is difficult.
(3) Lung cancer: The disease is generally found in smokers. The lung tissues growing abnormally and ultimately resulting in the death of the suffering person.
(4) Tuberculosis: It is a bacterial disease of lungs and is caused by Mycobacterium tuberculosis. These bacteria releasing tuberculin toxin which causes fever, loss of weight and weakness in the patient .

What is respiration? Explain the process of respiration in human beings. (Figure not required)

Respiration: The process of releasing energy by the oxidation of food is known as respiration. The process of respiration involves intake of oxygenated air into the cells for breaking the food and releasing energy.
Mechanism of respiration:
i. Air is drawn into the body through the nostrils.
ii. The air from the nasal cavity passes to the pharynx, which leads to the trachea, through a slit called glottis.
iii. The trachea runs down the neck and divides into two bronchi, which lead into the lungs and further divide into smaller bronchioles. The smallest bronchioles terminate into alveoli.
iv. The walls of the alveoli are thin and covered by blood capillaries to facilitate the exchange of gases in the lungs.
v. In the alveoli, the exchange of gases takes place, CO$$_2$$ from the blood is replaced with O$$_2$$ and CO$$_2$$ is removed out of the body.

vi. In humans, for the process of respiration, air is drawn into the lungs by the process of breathing.
When an individual inhales, the diaphragm moves down, and the chest cavity expands and the oxygen rich air is drawn into the lungs. When the individual exhales, the diaphragm relaxes and the chest cavity moves back to its relaxed position and the carbon dioxide rich air is expelled out of the body.

In earthworm, haemoglobin is present in

In earthworms, haemoglobin is the respiratory pigment which carries oxygen to different parts of the body. It is present in the blood plasma. The blood of the earth circulates through the vessels.

Explain the process of inspiration and expiration under normal conditions.

Regulation of respiration (inspiration and expiration):

In the brain, the medulla oblongata contains a respiratory centre. This controls breathing. The respiratory centre consists of an inspiratory centre and an expiratory centre. The axons from the nerve cells of these centres lead to the intercostal muscles through the intercostal nerves and the diaphragm via the phrenic nerves. These nerve fibres transmit impulses to the external intercostal and internal intercostal muscles alternately. The walls of the alveoli have sense endings, which are stimulated by changes in the tension of alveolar walls.

When the alveoli are stretched at the height of inspiration the receptors send stimuli to the expiratory centre of the medulla through the vagus nerve which inhibits further inspiration. This sequence of events is called Herring-Bruer reflex. In addition, the medulla contains a pneumotaxic centre, which s connected to the breathing centre and helps to ensure rhythmic breathing. During inspiration, the inspiratory part of the respiratory centre sends impulses to the pneumotaxic centre, which responds by sending impulses to the expiratory part of the respiratory centre. The expiratory centre is then activated and so the inspiratory centre is inhibited reflexly. Thus the respiratory rhythm is controlled by these centres in the brain.

Explain inspiration and expiration.

Inspiration and expiration are two processes involved in respiration. Inspiration is the process of taking in of the air and expiration is the breathing out of the air.
During inspiration, there is an increase in the volume of the thoracic area. The diaphragm becomes flattened and there is the relaxation of the intercostal muscles. This allows the increase in the thoracic cavity and allows the lungs to expand and take the air inside.
During expiration, there is a decrease in the volume of the thoracic cavity due to diaphragm being dome-shaped and contraction of the intercostal muscles. This allows the lungs to push the air outside.

Describe any four occupational respiratory disorders.

There are different types of occupational respiratory diseases.

i) Asbestosis: Due to excessive exposure to the asbestos fibres, there is accumulation in the lungs which results in this conditions.

ii) Silicosis: Due to inhalation of silica particles, there is lung disease which is known as silicosis.

iii) Asthma: This condition is due to the allergy of ant particulate or gaseous matter. This is a condition which may be developed due to the exposure to any material during the working in factories or mines.

iv) Pneumoconiosis: There is development of pneumonia due to the interaction with the coal particles in the mines.

Describe disorders of respiratory system.

There are different disorders which affect the respiratory system.

1. Obstructive disorder: The diameter of the bronchi becomes narrower and this blocks the airway. The common obstructive disorders are asthma, bronchitis, etc. There is difficulty in breathing.

2. Tuberculosis: This is the bacterial infection of the lungs by Mycobacterium tuberculosis. The disease cause formation of nodules in the lungs and the other respiratory surfaces. This results in the formation of pus and mucus which blocks the airway.

3. Respiratory tract infections: Common cold, tonsillitis, sinusitis, etc may result in the infection of the upper respiratory tract. The bacteria causing pneumonia may result in the infection of the lower respiratory tract.

Explain in brief transport of CO$$_2$$ in respiration.

Carbon dioxide is transported in form of carbamino haemoglobin. When the partial pressure of carbon dioxide is high it combines with the haemoglobin and gets transported as carbamino haemoglobin.

Carbon dioxide is also transported in form of bicarbonate. When the partial pressure of carbon dioxide is high at the tissue site, it diffuses into the blood and forms bicarbonate in the RBC. The enzyme carbonic anhydrase present in the RBC helps in the formation of bicarbonates.

Write the two functions of pericardial fluid.

Pericardium is a sac-like structure surrounding the heart. It consists of two layers. The outer layer is fibrous and is called as parietal pericardium. The inner layer is known as visceral pericardium and secretes a fluid called pericardial fluid.

Functions of pericardial fluid are-

1) The fluid minimizes the friction generated between the membrane during the process of contraction and relaxation of the heart.

2) It also absorbs the shock to protect the heart from mechanical injury.

How does the transportation of oxygen occur through blood?

Oxygen is carried by the erythrocytes of the blood. Oxygen combines with the haemoglobin present in these cells forming a compound called oxyhaemoglobin. Haemoglobin is a complex corn pound which has a great affinity for oxygen. Haemoglobin enables the blood to carry about so times more oxygen than the plasma alone can miry.
While passing through the alveolar capillaries haemoglobin becomes saturated with oxygen.
100ml of blood contains about zooms of oxygen:
$$\begin{matrix}Hb \\ Haemoglobin \end{matrix} + \begin{matrix} O_2 \\ Oxygen \end{matrix} \rightleftharpoons \begin{matrix} HbO_2 \\ Oxyhaemoglobin \end{matrix}$$
Oxyhaemoglobin is a very unstable compound when blood reaches in the tissue where oxygen tension is low. Oxyhaemoglobin breaks into haemoglobin and oxygen diffuse into the cells. The amount oxyhaemoglobin formed depends upon the partial pressure of oxygen in the blood. It has bright scarlet colour, while reduced haemoglobin has a dull purplish colour. This accounts for the colour difference between arterial and venous blood.

Why does an athlete breathe faster and deeper than usual after finishing the race?

Explanation:

During a run, the demand for energy is high but the supply of oxygen to produce energy is limited.
Therefore, anaerobic respiration takes place in the muscles cells to fulfil the demand for energy. Thus extra energy is required by his muscle cells which have worked hard during running.
Hence after finishing the race, an athlete breathes faster and deeper than usual so that more oxygen is supplied to the muscle cells and the further formation of lactic acid is inhibited.

What are mucus secreting cells?

The main role of goblet cells is to secrete mucus in order to protect the mucous membranes where they are found. Goblet cells accomplish this by secreting mucins, large glycoproteins formed mostly by carbohydrates.

Explain the process of inspiration under normal conditions.

Inspiration is the process of taking air from the atmosphere into the lungs. It is done by creating a pressure gradient between the lungs and the atmosphere. During inspiration, the diaphragm contracts and the space in the thoracic cavity increases. Along with this, there is contraction of the external intercostal muscles. This results in the outward movement of the ribs and the sternum. This increases the volume of the thoracic chamber in the dorsoventral axis. This ultimately results in increase in the pulmonary volume. Due to this, intrapulmonary pressure becomes lesser than the atmospheric pressure. This causes the inhalation of air from the atmosphere into the lungs.

Diffusion of gases occurs in the alveolar region only and not in the other part of respiratory system. Why?

For efficient exchange of gases, the respiratory surface must have certain characteristics such as (I) it must be thin, moist and permeable to respiratory gases. (ii) it must be very large (iii) it must be highly vascular. Only the alveolar region has these characteristics. Thus, diffusion of gases occurs in this region only.

Describe the mechanism of respiration in man.

Mechanism of respiration in man takes place in two phases, namely inspiration and expiration. Inspiration is the process of inhaling air into the lungs. During inspiration, the muscles of diaphragm contract and the diaphragm moves downward. This results in the increase in the volume of the chest cavity, The air pressure inside the chest cavity decreases. The oxygenated air present outside the body being at high-pressure flow rapidly into the lungs. In the lungs, oxygenated air reaches the alveoli. Alveoli are thin walled and are surrounded by a network of blood capillaries. The oxygen passes through the walls of the alveoli into the blood present in blood capillaries. The oxygen is then supplied to all the tissues of the body. From the tissues, the waste product, carbon dioxide is absorbed by blood and carried to the alveoli of lungs for expiration. Expiration is the process of exhaling air from lungs. During expiration, the muscles of diaphragm relax and diaphragm moves upward. This results in the decrease in the volume of the chest cavity. The air pressure inside the chest cavity increases. This pushes out carbon dioxide outside the body.

What is the breathing rate in man?

$$\textbf{Solution}$$

$$\bullet$$ Breathing rate or respiratory rate is the number of breath that a person take per minute.

$$\bullet$$ The typical breathing rate for a healthy human the breathing rate is around 12 to 18 breaths per minute.

$$\bullet$$ The respiration rate of the newborn baby is relative high which is around 60 breaths per minute.

$$\bullet$$ Higher breathing rate means having some kind of anxiety or lung infection and even heart failure.

Discuss the transport of gases ($$O_2$$ and $$CO_2$$) in the blood.

Oxygen enters the blood from the lungs and carbon dioxide is expelled out of the blood into the lungs. The blood transports both gases. Oxygen is carried to the cells. Carbon dioxide is carried away from the cells. Oxygen inhaled into the lungs bind to hemoglobin of the blood which flows through the lungs. This oxyhemoglobin reaches the tissues and releases most of its oxygen. In return, the carbon dioxide is given out by the tissues and enters the bloodstream. It diffuses out of the red blood cell and enters into the lungs in the form of bicarbonates. In the lungs, it is broken down and free carbon dioxide is liberated.

What is partial pressure? How does it help in gaseous exchange during respiration?

In a mixture of gases, the partial pressure is the amount of pressure each gas would exert if it were the only gas in the volume or we can defined as, it is the pressure exerted by each of the constituents of a mixture of gases. Partial pressure is related to the gaseous exchange of respiration i.e, as air moves into the alveoli, water vapor and carbon dioxide are added, and that reduces the partial pressure of oxygen to about 100 mmHg in the alveolar gas.

What is tidal volume?

Explanation:

Tidal volume (TV) is the amount of air that is moving in or out of the lungs with each respiratory cycle.
In other words, it is the amount of air that is inspired or expired during normal respiration.
A healthy man can inspire or expire approximately 6 to 8 L of air per minute.

How does exchange of respiratory gases take place in the alveoli or lungs?

The exchange of respiratory gases, oxygen, and carbon dioxide takes place in the alveoli of the lungs.
Oxygen which is inhaled from the atmosphere diffuses through the walls of the alveoli and reaches the adjacent capillaries into the red blood cells.
It binds to hemoglobin present in red blood cells and is transported to all the tissues of the body.
Carbon dioxide produced by the metabolism reaches the lung via the blood. It then diffuses across the capillary and alveolar walls into the air to be exhaled out from the body.
The alveoli of the lungs have a specialized structure for the efficient exchange of respiratory gases. It has extremely thin walls.
It has a large surface area to volume. It is surrounded by many blood capillaries.

Choose the odd one out:
Oxyhaemoglobin, Carbaminohaemoglobin, Hypoxia, Carboxyhaemoglobin

In the absence of oxygen or its low concentration the level of oxyhaemoglobin lowers and the level of carboxyhaemoglobin increases. It causes hypoxia

The carbaminohaemoglobin is formed when the $$CO_2$$ combines with the haemoglobin. It does not cause hypoxia. So, the odd one out is 'carbaminohaemoglobin'.

Name the body structure concerned with the given functional activity:
Protects the lungs from mechanical injuries

$$\textbf{Solution}$$

$$\bullet$$ The structure which is used to protect the lungs from mechanical injury is ribcage.

$$\bullet$$ The Rib cage is composed of ribs and sternum which are bones that covers the thoracic cavity.
$$\bullet$$ The Rib cage is a semi-rigid bony as well as cartilage in a structure which surrounds the thoracic cavity.
$$\bullet$$ The Rib cage helps in the protection of major vital organs such as heart, lungs and liver.
$$\bullet$$ So, the correct answer is rib cage.

Choose the odd one out in each of the following groups of four items each:
Hairy, Moist, Nostril, Vocal cord.

The nasal lining in the nostril is hairy and moist to stop particulate matter. The vocal cords have muscles for producing sound as air passes through it. So, the odd one out is 'Vocal Cord'.

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
Pleura and .........

The pleural cavity also contains pleural fluid, which acts as a lubricant and allows the pleurae to slide effortlessly against each other during respiratory movements. So, the correct statement is 'Pleura and protection of the lungs'

State one function of the following:
Ciliated epithelium lining the respiratory tract

Ciliated epithelium in the respiratory tract helps in mobilising the mucus and keeping the respiratory tract clear and unobstructed.

State one function of each of the following:
Intercostal muscles

The intercostal muscles contract and relax to change the size of the thoracic cavity by pulling the rib cage inwards and outwards. This allows inhalation and exhalation.

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
Epiglottis and .........

The main function of the epiglottis is to seal off the windpipe during eating, so that food is not accidentally inhaled. So, the correct statement is 'Epiglottis and sealing of the respiratory passage during swallowing'.

Match the items in Column A with those in Column B.
Column A Column B
A. Cartilaginous 1. Epiglottis
B. Large surface area 2. Diaphragm
C. Breathing movements 3. Bronchi
D. Voice 4. Alveoli
E. Complemental air 5. Larynx
F. Swallowing 6. Extra inhalation

	Column A		Column B
A.	Cartilaginous	3.	Bronchi
B.	Large surface area	4.	Alveoli
C.	Breathing movements	2.	Diaphragm
D.	Voice	4.	Larynx
E.	Complemental air	6.	Extra inhalation
F.	Swallowing	1.	Epiglottis

Give suitable explanations for the following:
Breathing through the nose is said to be healthier than through the mouth.

The hair and mucous lining in the nose helps in filtering out the dust particles and other particulate matter. This is absent when we breathe by mouth. This is the reason breathing through the nose is said to be healthier than through the mouth.

STRUCTURED/APPLICATION/SKILL TYPE
The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.
The following diagram shows a group of the lung volumes and capacities:
Study the diagram carefully and explain briefly the following:
Tidal volume

Tidal volume (symbol VT or TV) is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young human adult, tidal volume is approximately 500 mL per inspiration or 7 mL/kg of body mass.

Starting from the nostrils, trace the path in sequence which the inspired air takes until it reaches the air sacs.

$$\textbf{Solution:}$$

$$\bullet$$ The overall volume of the thoracic cavity increases due to the oscillatory contraction and relaxation of diaphragm, external intercostal muscles and abdominal muscles ,as a result these is a decrease in air pressure across the lungs .

$$\bullet$$ Therefore, greater pressure outside the body tends to cause air flow into the external nares from where the inspired air flow starts.Movement of inspired air from the atmosphere into the alveoli of the lungs is a sequential pathway that starts from the external nares (breathing in and out rhythmically ) from there it is passed in to the nasal cavity which opens into pharynx by means of internal nares.

$$\bullet$$ From pharynx is goes to trachea or windpipe followed by bronchioles which are the subdivision of bronchi and finally to the alveoli through alveolar duct. Therefore ,the pathway can be shown as :

External nares -----------> Nasal cavity -----------> Internal nares -----------> Pharynx -----------> Glottis -----------> larynx -----------> trachea -----------> bronchi -----------> bronchioles -----------> alveolar ducts -----------> alveoli.

Differentiate between the following pairs on the basis of the aspect given in the brackets.
Respiration and breathing (organs involved)

Breathing	Respiration
The process of obtaining oxygen and releasing carbon dioxide is called breathing.	The process of releasing energy from food is called respiration.
It is a physical process.	It is a biochemical process.
It takes place in the lungs.	It takes place in the lungs as well as in mitochondria.
It utilises energy from the food.	It releases energy from the oxidation of simple food.

Fill in the blanks with approriate words.
Each haemoglobin molecule can carry .......... molecules of oxygen, one in each ..........

Each hemoglobin molecule can carry four molecules of oxygen, one in each polypeptide.

Fill in the blanks with approriate words.
Lungs are covered with the covering of ..........

lungs are covered with the covering of pleural membrane. A pleura is a serous membrane that protects the soft organ it covers.

Fill in the blanks with approriate words.
Volume of air inspired and expired in a breath in normal respiration by man is called ..........

Tidal volume is the volume of air inspired and expired in a breath in normal respiration by man.

Fill in the blanks with appropriate words.

A mammal ventilates its lungs by moving it's ........... and ..........

A mammal ventilates its lungs by moving its rib cage and diaphragm.

Fill in the blanks with approriate words.
Glottis is closed during swallowing of food bolus by ..........

Glottis is closed during swallowing of food bolus by epiglottis.

STRUCTURED/APPLICATION/SKILL TYPE
The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.
The following diagram shows a group of lung volumes and capacities.
Study the diagram carefully and explain briefly the following:
Inspiratory reserve volume

The inspiratory reserve volume (IRV), about 3,100 mL, is the additional air that can be forcibly inhaled after the inspiration of a normal tidal volume.

Fill in the blanks with approriate words.
Sound is produced by vibrations of .......... located in the ..........

$$\textbf{Solution:}$$ Sound is produced by vibrations of vocal cords located in the larynx.

$$\textbf{Explanation:}$$

$$\bullet$$ Vocal cords are stretchy flaps of skin in your throat that vibrate to make a sound.

$$\bullet$$ Sound is produced when the air which passes through the vocal cords causes them to vibrate and create sound waves in the pharynx, nose and mouth.

$$\bullet$$ When an object vibrates, it necessitates the surrounding particles of the medium to vibrate. The particles that are adjacent to vibrating particles are forced to vibrate.

$$\bullet$$ Hence the sound produced by a vibrating object in a medium is transferred from particle to other particle till it reaches your ear.

STRUCTURED/APPLICATION/SKILL TYPE
The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.
The following diagram shows a group of lung volumes and capacities.
Study the diagram carefully and explain briefly the following:
Expiratory reserve volume

The extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal, quiet expiration. Common abbreviation is ERV.

The metal associated with haemoglobin protein is ..........

The metal associated with hemoglobin protein is iron.

Fill in the blanks with approriate words.
In humans, the trachea is strengthened by incomplete .......... rings.

In humans, the trachea is strengthened by incomplete cartilaginous rings.

Fill in the blanks with approriate words.
Exhalation from the lungs takes place when the size and pressure of the thoracic cavity is ..........

Exhalation takes place from the lungs when the size and pressure of the thoracic cavity are reduced.

Fill in the blanks with approriate words.
Inflammation in the outer covering of lungs is known as ..........

Inflammation in the outer covering of lungs is known as pleurisy.

Fill in the blanks with approriate words.
In lungs, the inspired air ultimately reaches to ..........

in lungs, the inspired air reaches to alveoli where diffusion takes place.

Fill in the blanks with approriate words.
Lungs lie in the thoracic cavity separated by .......... from the abdominal cavity

Lungs lie in the thoracic cavity. The thoracic cavity is separated from abdominal cavity by diaphragm.

Fill in the blanks with approriate words.
The most characteristic feature of haemoglobin is its ability to combine reversibly with ..........

The most characteristic feature of hemoglobin is its ability to combine reversibly with oxygen.

Very short answer type.
What term is used for the volume of air breathed in and out during each normal effortless respiration?

Volume of air that is breathed in and out during each normal effortless respiration is called tidal volume.

Very short answer type.
Name the structure that contains vocal cords.

Vocal cords are contained by a structure named larynx. Vocal cords are membranous folds that vibrate when air is passed, resulting in the production of sound.

Very short answer type.
Which structures are part of the conducting portion of the respiratory system?

Nose, pharynx, larynx, trachea, bronchi, and bronchioles.

Very short answer type.
How does the epiglottis prevent foods and liquids from entering the larynx?

During swallowing, the epiglottis closes over the larynx.

Discuss the significance of haemoglobin in respiration.

Haemoglobin, present in R.B.C.s, combines with oxygen in the lungs and is converted into oxyhaemoglobin. This blood is termed pure or oxygenated blood. Haemoglobin is the carrier of oxygen to all the living cells for cellular respiration.
Oxygen present in haemoglobin is used and carbon dioxide released during cellular respiration combines with haemoglobin. This blood is termed impure or deoxygenated blood.
This impure blood is carried to the lungs. Haemoglobin releases carbon dioxide and combines with oxygen and is converted into oxyhaemoglobin again to be carried to all living cells through blood circulation.

Differentiate between external respiration and internal respiration.

In external respiration there is uptake of oxygen from the surrounding environment (air or water medium) and elimination of carbon dioxide into that medium. The exchange of gases takes place by diffusion across the general body or respiratory surfaces. It is a purely physical process and in this process no energy is produced.

In internal respiration there are both oxidative and non-oxidative enzymatic reactions by which energy is. made available to maintain the various vital activities. It is a physio-chemical process and in this process energy is produced.

Short / long answer type questions.
Draw a neat labelled diagram of human respiratory system.

The given diagram represents the human respiratory system.
1380537_856387_ans_c895b2ca1aba4f9e818f469c8bc8de25.jpeg

Very short answer type.
How many molecules of oxygen can one haemoglobin molecule transport?

Four-one bound to each heme group.

Give reasons for the right and left shift in the oxygen–hemoglobin dissociation curve.

Oxygen-haemoglobin dissociation curve is used to study the percentage saturation of oxygen to hemoglobin. A right shift indicates decreased oxygen affinity of haemoglobin allowing more oxygen to be available to the tissues. It may be due to following reasons: increased temperature, increased hydrogen ion concentration. A left shift indicates increased oxygen affinity of haemoglobin allowing less oxygen to be available to the tissues. It is due to the following reasons: decreased temperature, decreased hydrogen ion concentration.

Short / long answer type questions.
Give the definition and normal values of lung volumes and lung capacities.

There are following respiratory volumes and capacity :

1. Tidal volume (TV): It is the volume of air normally inspired or expired in one breath (i.e. inspiration and expiration) without any extra effort. It is about 500 ml in the normal healthy adult.

2. Inspiratory reserve volume (IRV): By taking a very deep breath, you can inspire a good deal more than 500 ml. This additional inhaled air, called IRV is about 3000 ml.

3. Expiratory reserve volume (ERV): If you inhale normally and then exhale as forcibly as possible, you should be able to push out 1200 ml of air in addition to 500ml. of T.V. The extra 1200 ml is called ERV.

4. Residual volume (RV): Even after expiratory reserve volume is expelled, considerable air remains in the lung, this volume, which cannot be measured by spirometry, and it is called residual volume is about 1200 ml.

5. Functional residual capacity (FRC): It is the amount of air that remains in the lungs after a normal expiration. It is about 2300 ml.

FRC = ERV + RV = 1100 + 1200 = 2300 ml.

6. Vital capacity (VC): This is the maximum amount of air that can be expired forcefully from his lungs after first filling these with a maximum deep inspiration. It is about 4600 ml.

VC = IRV + TV + ERV

= 3000+500+1100 = 4600 ml.

7. Total lung capacity (TLC): TLC is the sum of vital capacity (VC) and residual volume (RV). It is about 5800ml.

TLC = VC + RV

= 4600 + 1200 = 5800 ml.

8. Inspiratory capacity (IC): It is the total amount of air a person can inspire by maximum distension of his lungs.

I.C. = TV + IRV

Short / long answer type questions.
Gaseous exchanges continue in lungs without interruption even during expiration. Explain.

The gaseous exchange continues in the lungs even during expiration because expiration is the result of reverse movements of the ribs and diaphragm. As a consequence of the movements of the ribs and the diaphragm, the thoracic cavity is diminished and the lungs are compressed, forcing the air out into the atmosphere.

Very short answer type.
Why are the right and left lungs slightly different in shape?

Since two-thirds of the heart lies to the left of the midline, the left lung contains a cardiac notch to accommodate the position of the heart.

Dissociation of oxyhaemoglobin is more in an active tissue than in a less active one. Give reason.

An active tissue site has an increased partial pressure of carbon dioxide and reduced partial pressure of oxygen. Both these factors favor the dissociation of oxyhaemolobin at the site into deoxyhaemoglobin and molecular oxygen.

Short / long answer type questions.
Man can live without food for a few days but cannot live without oxygen for even a few minutes. Why?

There is already stored food in the form of fats, which can be degraded by the body when there is a scarcity of energy. But oxygen is not stored in our body, so we need to get it constantly in order to survive. Oxygen is constantly required to keep the body in working state because of its role in energy production through food metabolism.

Match the terms to these definitions.
Anaerobe, aerobe, kiss of life, spirograph, inspiration, chloride shift, tidal volume, oxygen debt tidal air.
.......... The drawing in of the breath

inspiration

Match the terms to these definitions.
Anaerobe, aerobe, kiss of life, spirograph, inspiration, chloride shift, tidal volume, oxygen debt tidal air.
.......... That air which is inspired and expired during normal breathing.

tidal volume

When you go far a trek/trip to any high altitude places, you are advised to take it easy and rest for the first two days. Comment giving reasons.

Partial pressure of oxygen is low at higher altitudes so, if we do not give time to our body to adapt new conditions we can suffer from altitude sickness. So a rest of two days is advised.

Give the differences between right and left lungs of humans.

Right lung	Left lung
It has three lobes namely, upper, middle and lower.	It has two lobes, upper and lower.
It has deep concavity on the inner surface that is called the cardiac impression	It is less concave than right lung.
It has two bronchi.	It has one bronchus.
It is shorter and wider in shape.	It is narrower and is oblong in shape.

Draw a schematics representation of transport and exchange of oxygen and carbon dioxide in human body.

In human body, gaseous exchange occurs between tissue cells and the capillary blood through intestinal fluid and this is called internal respiration. The exchange occurs due to difference in partial pressure of the gases. Partial pressure is the pressure contributed by an individual gas in a mixture of gases. It is represented as p‎O₂ for oxygen and pC‎O₂for carbon dioxide. Gases diffuse from high partial pressure to low partial pressure.
948675_1018751_ans_6488323a610f49fcb6e7fdac29e4b551.png

948675_1018751_ans_6488323a610f49fcb6e7fdac29e4b551.png

Identify and describe the function of the parts marked P,Q,R and S

P: Pharynx - Pharynx is the common passageway for air and food, thus having a role in both respiratory and digestive systems. In the respiratory system, the main role of the pharynx is to allow the inhaled air entering the nasal cavity to move to the respiratory tract.

Q: Larynx - Larynx plays a vital role in the respiratory system, by allowing the passage of air through the respiratory tract and preventing the blocking of the airway by food and drinks. Larynx also houses vocal folds and manipulate the pitch and volume of the sound, thus it is also called the organ of phonation or the voice box.

R: Trachea - Trachea or the windpipe is a hollow tube that connects larynx to the bronchi of the lungs. It provides the air passage to the lungs for respiration, i.e., inhalation of oxygen-rich gas and the exhalation of the carbon dioxide-rich gas.

S: Bronchi - Bronchi are small branching airways that evolve into tiny air sacs called alveoli, which is the site of oxygen and carbon dioxide exchange into bloodstream in the respiratory system.

Explain the process of external respiration.

External respiration is referred to as oxygen diffuses into the blood while carbon dioxide diffuses into the alveolar air. Here the concentration of hydrogen ion and the temperature is reduced and partial pressure of oxygen is high it helps the oxygen to diffuse from the three layers of alveoli to blood and carbon dioxide concentration is greater on blood capillaries side while less at alveoli so it diffused inside and release outside through expiration.

Name the sound producing organ of human being?

Sound producing organ of human being is the larynx. It is a cartilaginous box and is also known as the sound box. There are two vocal cords in the box which vibrate on the passage of air through them and hence produce sound.

Describe the mechanism of respiration in humans.

Mechanism of respiration involves five steps:-

Breathing or pulmonary ventilation: It involves both inhalation in which an adequate amount of oxygen is taken inside and exhalation involves removal of carbon dioxide with air.
External respiration: This is the exchange of oxygen to the blood and of carbon dioxide from blood to alveoli and is done due to their concentration gradient.
Transport of O$$_2$$ to tissue: Oxygen binds to haemoglobin and reaches to tissues.
Internal respiration: As the concentration of oxygen is less and carbon dioxide is more in number the haemoglobin release oxygen and is absorbed by the tissue.
Transport of CO$$_2$$ from tissue:- The carbon dioxide released by tissue transported in the form of bicarbonate, carbamino-haemoglobin and dissolved in the blood reaches to alveoli then diffuse from blood and released out.

Give reason why alveoli are surrounded by blood capillaries?

As per the structure of the lungs, the windpipe (trachea) branches into two bronchi (one to each lung). The bronchi split into smaller and smaller tubes called bronchioles. The bronchioles end in microscopic air sacs called alveoli.

These air sacs are lined with mucus and are surrounded by a network of blood capillaries.

The mucus surface of the alveoli allows oxygen to dissolve in it.

They have a very thin lining to allow oxygen to diffuse into the blood easily.

And surrounding blood capillaries pick up and transport oxygen.

There is an exchange of gases between the air sacs and their surrounding capillary blood vessels. Oxygen diffuses from the air sac into the blood. Carbon dioxide diffuses from the blood into the air sac.

The capillary network allows efficient gas exchange in tissues since they have a large surface area and they have thin walls.

Explain the mechanism of inspiration.

Mechanism of inspiration:

(a) The process of intake of atmospheric air is known as inspiration. It is an active process
(b) When the volume of the thoracic cavity increases and the air pressure decreases, inspiration takes place
(c) Contraction of external intercostal muscles increases the volume of the thoracic cavity.
(d) Contraction of the diaphragm further increases the size of the thoracic activity. Simultaneously, the lungs expand.
(e) With the expansion of the lungs, the air pressure inside the lungs decreases
(f) The pressure equalizes and the atmospheric air rushes inside the lungs

Explain how does the air we breathe in, gets cleaned while passing through the nasal passage.

The nasal passage which is separated from the oral cavity by a hard and bony palate. The passage is lined by the epithelium cells which contain hair and mucous as well which helps in the traping of dust particles and also moisten it. This is the way in which the air we breathe, gets cleaned.

Write the factors which affect rate of diffusion of $$O_2$$ and $$CO_2$$ in alveoli.

There are some factors which affect the rate of diffusion. These are:-

The partial pressure of oxygen.
The partial pressure of carbon dioxide.
Temperature.
The concentration of gases.
The thickness of the membrane.

Respiratory surface of animals must always be moist. Why?

In animals, the process of respiration is aerobic respiration, exchange of gases takes place( carbon dioxide leaving the cell, oxygen entering)

Single cellular organisms can exchange gases directly across their cell membrane through the process o diffusion.

Large animals cannot maintain gas exchange by diffusion across their outer surface. A respiratory surface is covered with thin, moist epithelial cells that allow oxygen and carbon dioxide to exchange. Those gases can only cross cell membranes when they are dissolved in water or an aqueous solution, thus respiratory surfaces must be moist.

Explain the respiratory volumes and capacities.

Capacity	Definition	Equivalent value
Inspiratory Capacity	The total volume of air a person can inspire after a normal expiration.	TV+IRV
Expiratory Capacity	The total volume of air a person can expire after a normal inspiration.	TV+ERV
Functional Residual Capacity	The volume of air that will remain in the lungs after a normal expiration.	ERV+RV
Vital Capacity	The maximum volume of air a person can breathe in after a forced expiration.	ERV+TV+IRV
Total Lung Capacity	The total volume of air accommodated in the lungs at the end of a forced inspiration	RV+ERV+TV+IRV

Respiratory Volume

Volume	Definition	Approx value
Tidal Volume	The volume of air inspired or expired during a normal respiration	6000-8000 ml of air per minute.
Inspiratory Reserve Volume	The additional volume of air, a person can inspire by a forcible inspiration.	2500-3000 ml
Expiratory reserve volume	The additional volume of air, a person can expire by a forcible expiration.	1000-1100 ml
Residual Volume	The volume of air maintaining in the lungs even after a forcible expiration.	1000-1200 ml

What is oxygen dissociation curve? List the factors which result in causing this curve.

Oxygen dissociation curve is the graph plotted between tha partial pressure of oxygen and saturation of haemoglobin with oxygen. It is a sigmoid curve.

Various factors that effects this graph are :-

Partial pressure of oxygen.
Partial pressure of carbon dioxide.
Concentration of hydrogen ions.
Temperature.

List the functions of Nasal Cavity.

The main function of the nasal cavity is to moderate the temperature of the inhaled air.

• The nasal mucous membrane moistens the air as it passes through.

• The nasal mucous membrane and hairs trap the dust and other particulate matter and cilia transfer the trapped particles to the pharynx from where it passes to bronchii and then the lungs.

Describe exchange of gases at alveolar level.

In the respiratory system of humans, alveoli in the lungs are the site of gaseous exchange.
It is a thin-walled, sac-like structure lined by a single layer of flattened squamous epithelial cells.
Oxygen-rich air enters the lungs and reaches the alveoli.
The layers of cells lining the alveoli and the surrounding capillaries are each only one cell thick and are in close contact with each other.
Oxygen diffuses through the cells to the pulmonary capillaries due to the difference in the concentration gradient of oxygen molecules in the blood capillaries and the alveoli which are carried to different cells of the body.
Similarly, the pulmonary capillaries contain carbon-dioxide-rich air brought from different parts of the body as an end product of respiration.
This carbon-dioxide in the pulmonary capillaries diffuse into the alveoli due to the difference in the concentration gradient and are later exhaled out.

Observe the following equation given and write a short note on it.
$$Hb + 4O_2 \rightarrow Hb(O_2)_4$$ (In lungs)
$$Hb(O_2)_4 \rightarrow Hb + 4O_2$$ (In tissues)

Oxygen that diffuses into blood binds to haemoglobin molecules packed into red blood cells and is moved around the body. Haemoglobin is a globular protein with four haem molecules held in it by intermolecular bonds. In

the concentrations of oxygen found in the lungs, oxygen molecules bond to the iron(II) ions in the haem molecules to form oxyhaemoglobin.

One haemoglobin molecule carries four oxygen molecules. About 98.5% of the oxygen in blood is transported as oxyhaemoglobin. In the lower concentrations of oxygen found in respiring tissues, the oxyhaemoglobin dissociates to release oxygen.

Which organ is called voice box?

Voicebox is a tube-shaped organ present in the neck.
The organ that forms the voice box is the larynx.
It is a part of the respiratory tract which contains the vocal cord that produces sound.
It is located between the pharynx and the trachea.

Describe in brief the function of ribs and diaphragm in breathing.

The act of breathing is performed primarily by the diaphragm, a large muscle that separates the thoracic cavity from the abdominal cavity and also by the movement of the ribs.

During inspiration the diaphragm contracts and becomes flat, creating a vacuum in the thoracic cavity. This vacuum inflates the lungs by drawing air into the body through the trachea, or windpipe.

During normal expiration, the diaphragm relaxes allowing the air to flow out as the lungs deflate.

The ribs protect the lungs and expand as we inhale to facilitate space for the lungs to expand like the diaphragm. The ribs then contract expelling the air in the lung.

Many persons like to use asthma as an excuse for not being able to do well in sports. Try telling them about Down Fraser, who was the first women to break 60 sec in 100 m freestyle swimming. The first women to win four Olympic gold medals and the first swimmer to win the same event in three consecutive Olympics was asthmatic.
On the basis of the above passage, answer the following question..
i) Describe her achievements in the field of swimming.

Dawn Fraser is called as Australian sports legend. She was the first woman to break 60 seconds in 100 m free style swimming. She has won Olympics for consecutive 3 years despite having asthma. In total, she has won 4 Olympic gold medals.

Mechanism of breathing very among different groups of animals depending on :

Breathing involves two stages:

INSPIRATION:

Inspiration during which atmospheric air is drawn in.
At the time of inspiration, contraction in diaphragm and external intercostal muscles takes place.
Normally it takes around 2 seconds.

EXPIRATION:

Expiration is a process by which the alveolar air is released out.
At the time of expiration, contraction does not take place.

1059982_1105932_ans_5a2f20cd8adb4c39a2c0a6694e1fddd8.jpg

Many persons like to use asthma as an excuse for not being able to do well in sports. Try telling them about Down Fraser, who was the first women to break 60 sec in 100 m freestyle swimming. The first women to win four Olympic gold medals and the first swimmer to win the same event in three consecutive Olympics was asthmatic.
On the basis of the above passage, answer the following question.
i) What do you mean by asthma?

Asthma is a chronic lung disorder. In this, the bronchi of the lungs become inflamed. The airways of the lungs are swollen and produce thick mucus. The symptoms include shortness of breath, cough, wheezing, difficulty breathing.

Explain respiratory system of human.

$$\textbf{RESPIRATORY SYSTEM OF HUMANS} $$

The respiratory system is the network of organs and tissues that help individuals to breathe. This system helps the body to absorb oxygen from the air and supply it to different body organs. It also cleans waste gases, such as carbon dioxide from the blood.

$$\textbf{Components of the respiratory system are} $$-

$$\bullet$$ Mouth and nose: Openings that allow the air from outside to enter into the body.

$$\bullet$$ Sinuses: Hollow areas between the bones in the head that help to regulate the temperature and humidity of the inhaled air.

$$\bullet$$ Pharynx (throat): Tube that delivers air from mouth and nose to the trachea (windpipe).

$$\bullet$$ Trachea: Connecting passage between throat and lungs.

$$\bullet$$ Bronchial tubes: Tubes at the bottom of the trachea connecting into each lung.

$$\bullet$$ Lungs: Paired organs that remove oxygen from the air through alveoli and pass it into the blood.

Bones and muscles in the respiratory system include that help in inhalation and exhalation:

$$\bullet$$ Diaphragm: Muscle present in the abdomen just below the lungs that helps lungs pull in air and push it out.

$$\bullet$$ Ribs: Bones that surround lungs and heart and function in protecting them.

$$\textbf{Components that work with the lungs and blood vessels that help in the exchange of oxygen and carbon dioxide include} $$:

$$\bullet$$ Lung lobes: Sections of the lungs —

a) Three lobes in the right lung

b) Two in the left lung

$$\bullet$$ Bronchioles: Small branches of the bronchial tubes that lead to the alveoli where actual diffusion takes place.

$$\bullet$$ Alveoli: Tiny air sacs in the lungs where the exchange(diffusion) of oxygen and carbon dioxide takes place.

$$\bullet$$ Capillaries: Blood vessels present in the alveoli walls that move oxygen and carbon dioxide throughout the body.

$$\bullet$$ Pleura: Thin layer that surrounds each lung lobe and separates your lungs from the chest wall.

$$\textbf{Other components of the respiratory system include} $$:

$$\bullet$$ Cilia: Tiny hairs present in the nostrils that move in a wave-like motion to filter dust and other irritants out.

$$\bullet$$ Epiglottis: Tissue flap at the entrance to the trachea that closes when you swallow to keep food and liquids out of your airway and inhibit any choking.

$$\bullet$$ Larynx (voice box): Hollow organ that helps to produce sounds when air moves in and out.

$$\textbf{Besides helping in inhalation (breath in) and exhalation (breathe out), the respiratory system has many functions like} $$

$$\bullet$$ Maintenance of temperature and humidity of the inhaled air.

$$\bullet$$ Helps in delivering oxygen to the cells in the body.

$$\bullet$$ Protection of the airways from harmful substances and irritants.

What is asthma?

Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms like reversible airflow obstruction and bronchospasm. Symptoms include wheezing, coughing, chest tightness and shortness of breath.

Briefly explain the structure of human lungs.

The lungs are a couple of light, air-filled organs situated on either side of the chest (thorax). The trachea (windpipe) conducts breathed in air into the lungs through its rounded branches, called bronchi. The bronchi at that point separate into littler and littler branches (bronchioles), at long last getting to be tiny.

The bronchioles in the long run end in groups of tiny air sacs called alveoli. In the alveoli, oxygen from the air is assimilated into the blood. Carbon dioxide, a waste result of digestion, ventures out from the blood to the alveoli, where it tends to be breathed out. Between the alveoli is a thin layer of cells called the interstitium, which contains veins and cells that assistance bolster the alveoli.

The lungs are secured by a thin tissue layer called the pleura. A similar sort of thin tissue lines within the chest depression - likewise called pleura. A thin layer of liquid goes about as an oil enabling the lungs to slip easily as they extend and contract with every breath.

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Describe the different respiratory organs found in insects and human beings.

Insects have tracheal system for respiration where a branched series of tubes that are filled with air except at the very end are present.
The trachea are branched into tracheoles which are constructed from a single invaginated cells are fluid filled this is where the exchange of gases take place.
The tracheoles are present near every cell no cell in the insect body is more than 2 or3 cell diameter away.
Tissues that have high metabolism like flight muscle, limbs, etc may have at least one terminal tracheole penetrating each cell, which means that oxygen is all the time avalible to all the cells of the body.

The respiratory organs of the humans are lung which perform pulmonary respiration in humans
They are localized in one area of the body and circulatory system does the work of transporting the gas from the lungs to other organs of the body and from the organs of the body to the lungs.
Air exchange in the lungs takes place via flow of tidal volume of air which takes place by the process of negative pressure breathing where the air enters the lung cavity when the pressure inside the lung is less than that of the atmosphere.

Discuss about the process of inspiration.

Normal breathing involves alternate inhalation or expiration and exhalation or expiration.
It involves the following muscles-

1) The major muscle responsible for breathing (inhalation and exhalation) is the diaphragm'

It is a dome-shaped thin muscle which separates the abdominal cavity and the thoracic cavity.
At the time of inhalation, the diaphragm contracts which compresses the abdominal cavity and raises the ribs upward and outwards to expand the thoracic cavity.
This expansion causes air to be drawn into the lungs.
As the diaphragm relaxes, the thoracic cavity contracts and forces the air to move out of the lungs

2) The intercostal muscles are attached between the ribs and are helps in increasing and decreasing the width of the rib cage.

The contraction of the external intercostal muscle fibres raises each rib toward the rib above and thus, raising the rib cage as well as assists in inhalation.
The internal intercostal muscle fibres assist in lowering the rib cage and causes exhalation.
During inspiration, the expansion of the thoracic cavity decreases the intra-alveolar pressure below the atmospheric pressure.

Which row in the table shows the correct percentage of oxygen in atmospheric and exhalend air ?
Atmospheric air / % Exhaled air /%
A 78 21
B 21 16
C 16 4
D 4 0.04

Inhaled air is by volume 78.08% nitrogen, 20.95% oxygen and small amounts include argon, carbon dioxide, neon, helium, and hydrogen. so, 'the correct option is atmospheric /% - 78 and exhaled air/ % - 21'

Explain the process of exchange of gases with the help of a diagrammatic representation of the human respiratory system.

Alveoli are the primary sites of exchange of gases. Exchange of gases also occur between blood and tissues.
O$$_{2}$$ and CO$$_{2}$$ are exchanged in these sites by simple diffusion mainly based on pressure/concentration gradient.
The solubility of the gases, as well as the thickness of the membranes involved in diffusion, are also some important factors that can affect the rate of diffusion.

Pressure contributed by an individual gas in a mixture of gases is

called partial pressure and is represented as pO$$_{2}$$ for oxygen and pCO$$_{2}$$ for carbon dioxide.

a gradient is present for CO$$_{2}$$ in the opposite

direction, i.e., from tissues to blood and

blood to alveoli. As the solubility of CO$$_{2}$$ is

20-25 times higher than that of O$$_{2}$$ the

amount of CO$$_{2}$$ that can diffuse through the

diffusion membrane per unit difference in

partial pressure is much higher compared

to that of O$$_{2}$$.

The diffusion membrane is

made up of three major layers

namely, the thin squamous epithelium of

alveoli, the endothelium of alveolar capillaries

and the basement substance in between

them. However, its total thickness is much

less than a millimetre. Therefore, all the

factors in our body are favourable for

diffusion of O$$_{2}$$ from alveoli to tissues and that

of CO$$_{2}$$ from tissues to alveoli.

1086256_1212991_ans_bac8071ae8924c7d9864782c5c9ea09a.jpg

With the help of labelled diagram explain the structure of human respiratory system.

Human Respiratory system consists of a pair of external nostrils opening out above the upper lips.
It leads to a nasal chamber through the nasal passage. The nasal
chamber opens into the pharynx, a portion of which is the common
passage for food and air.
The pharynx opens through the larynx region
into the trachea.
The larynx is a cartilaginous box which helps in sound
production and hence called the sound box.
During swallowing, glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the larynx.
The trachea is a straight tube extending up to the mid-thoracic cavity, which divides at the level of 5th thoracic vertebra into a right and left primary bronchi.
Each bronchus undergoes repeated divisions to form the secondary and tertiary bronchi and bronchioles ending up in very thin terminal bronchioles
The tracheae, primary, secondary and tertiary bronchi, and initial
bronchioles are supported by incomplete cartilaginous rings. Each
terminal bronchiole gives rise to a number of very thin, walled and vascularised bag-like structures called alveoli.
The branching network of bronchi, bronchioles and alveoli comprise the lungs.
We have two lungs which are covered by a double-layered pleura,
with pleural fluid between them. It reduces friction on the lung surface.
The outer pleural membrane is in close contact with the thoracic cavity.
The inner pleural membrane is in contact with the lung
surface.
The part starting with the external nostrils up to the terminal bronchioles constitute the conducting part whereas the alveoli and the ducts form the respiratory or exchange part of the respiratory system.
The conducting part transports the atmospheric air to the alveoli, clear it from foreign particles, humidifies and also brings the air to body temperature.

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The respiratory centre may release motor impulses of faster breathing due to?

The respiratory centre may release motor impulses of faster breathing under the influence of adrenaline, stress or lower amount of oxygen.
The overall effect of adrenaline is to prepare the body for the ‘fight or flight’ response in times of stress, i.e. for vigorous and/or sudden action.
Key actions of adrenaline include increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs, enlarging the pupil in the eye, redistributing blood to the muscles and altering the body’s metabolism.
In case of lowered oxygen, the respiratory centre stimulates faster breathing to compensate the oxygen loss.

Why is it better to breath through your nose than your mouth?

Mouth breathing doesn’t warm and moisturize air as efficiently as nose breathing, so the air is more likely to irritate the lungs. Also, breathing through the nose helps filter out dust and other allergens.

Describe the human respiratory system.

Respiratory system is responsible for the process of respiration. It involves exchange of gases, i.e, oxygen and carbon dioxide between body and surrounding. The body can't store oxygen, so, it is vital process and it is occurs all the time.
The body takes up oxygen and passes it to whole body through blood.
Respiratory system is divided into 2 major parts, upper respiratory tract and lower respiratory tract.
Upper respiratory tract is composed of nose, pharynx and larynx.

Nasal cavity traps the dust particles. Air passes to lungs through pharynx, and larynx is essential for speech

Lower respiratory tract is composed of the trachea, the lungs, and bronchioles including alveoli.
Trachea is the main pathway to lungs. Lungs are main site of gaseous exchange, they gives oxygen to capillaries and exhale carbon dioxide, Bronchi supply the lungs with air. Bronchioles are the branches of bronchus. They further branches into primary and secondary bronchioles. And they finally terminate into alveoli. Diaphragm contracts and relaxes to allow air into the lungs.

Fill in the blanks on a similar pattern.
a) Alveoli and ......
b) Mitochondria and .....
c) Epiglottis and .....

a) Alveoli and alveolar ducts are similarly based on their structure as alveoli form clusters called alveolar sacs, that resemble bunches of grapes. By the same analogy, the alveolar ducts leading to a sacs-like structure which seems like the stems of individual grapes.

b) Mitochondria and chloroplast are similar because both the organelles have their own DNA which is separate from the DNA found in the nucleus. And both the organelles use their own DNA to synthesize protein and enzymes required for their function.

c) Epiglottis and Pharynx are similar because the posterior surface of epiglottis facing the larynx but during swallowing, it serves as a part of interior of the pharynx.

What would happen if the lungs fail to work?

The lung performs the essential function of removing carbon dioxide from the body tissues and provide oxygen to the different tissues and organs of the body. If the lungs fail to work, this function will not be performed and will, in turn, lead to failure of organs such as heart and brain to function as they need oxygen to perform their function.

Where does the blood absorb oxygen in the human body?

Blood absorbs oxygen in alveoli present in the lungs. These are small organelles present in the lungs of the human body. These are the tiny air sacs present in the lungs.

Fill in the blank on a similar pattern.
Pleura and ________.

Pleural fluid

How does the mechanism of production of sounds in birds differ from that in human beings?

The mechanism of producing sound in birds differ from that in human beings because birds have a ring of cartilage called syrinx in their windpipe they use it in their voice Box to produce sound but in human beings there is a vocal chords or larynx which help us to produce sound.

Give an account of the disorder of human respiratory system.

(Any two).

Common Respiratory Disorders Include: Chronic Obstructive Pulmonary Disease(COPD) - Irritation of the lungs can lead to asthma, emphysema, and chronic bronchitis and people can develop two or three of these together.
Chronic bronchitis -Any irritant reaching the bronchi and bronchioles will stimulate increased secretion of mucus. In chronic bronchitis, the air passages become clogged with mucus, and this leads to a persistent cough.
Emphysema - The delicate walls of the alveoli break down, reducing the gas exchange area of the lungs. The condition develops slowly and is seldom a direct cause of death.
Asthma - Periodic constriction of the bronchi and bronchioles makes it more difficult to breathe.
Pneumonia - An infection of the alveoli. It can be caused by many kinds of both bacteria and viruses. Tissue fluids accumulate in the alveoli reducing the surface area exposed to air. If enough alveoli are affected, the patient may need supplemental oxygen.

Name the structure which is commonly called sound box

The structure which is commonly called sound box. Larynx is another name for the sound box. It is a tube about $$2$$ inches $$(5\,cm)$$ long in adults. It silts above the windpipe in the neck and in front of the food pipe.

With regard to the respiratory system and the process of respiration in man, answer the following question.
Name the two muscles that help in breathing.

Diaphragm contracts (tightens) and moves downward when we breathe in or inhale. This improves our chest cavity's room into which our lungs expand. Also, the intercostal muscles between our ribs assistance to increase chest cavity. When we inhale, they contract to pull our rib cage up and out. The muscles that assist inspire air are diaphragm and intercostal muscles. The diaphragm contracts pulling the thoracic cavity floor inferior during inspiration. This generates a vacuum that can be used to fill the air inhaled. During inspiration, the intercostal muscles elevate the lungs, thus helping the inhaled air get into the lungs.

What will happen if the respiratory tract is not moist?

For maximum effectiveness, the respiratory surface requires humidity. Oxygen from the air dissolves momentarily in the surface water, allowing more time for the oxygen to cross the membrane of the alveoli. If the surface dries out, the exchange of gas will take place at a very low pace as fast-moving gaseous oxygen molecules do not cross the alveoli membrane effectively. The decreased exchange of gas is most probably not sufficient for essential functions to promote blood oxygenation. If the respiratory tract is not wet, the dirt particles in the inhaled water in the nasal cavities will not be removed from the atmosphere and will reach the lungs and cause lung issues.The temperature of the inhaled air for the soft passage in the respiratory tract is carried close to that of the body. It's not feasible if it's dry.If the surface dries out, the exchange of gas will take place at a very low pace as quickly moving gaseous oxygen molecules do not cross the alveoli membrane effectively. The decreased exchange of gas is most probably not sufficient for essential functions to promote blood oxygenation.Therefore, for smooth exchange of gases, the respiratory tract should be wet.

What are the functions of the following in breathing?
Abdominal muscles.

The function of abdominal muscles is forced respiration by raising and lowering the ribs. Contraction of these muscles forces the contents of the abdomen upwards, reducing the volume of the chest cavity and leading to contraction of the lungs for expiration.

Give appropriate biological/technical terms for the following.
The membrane that encloses the lungs.

The pleural membranes are the two layers of serous membrane which encloses and protects the lungs. It plays a major role in lubrication and the reduction of friction between the body parts.

The outer layer is called the Parietal Pleura and the inner layer is called the Visceral Pleura.

Why are alveoli so small and uncountable in numbers?

To increase the exchange of gases in the lungs, alveoli are uncountable in number. They are too tiny to fit in alveolus numbers and boost gas exchange. The body can absorb much more oxygen than just two enormous ' empty bags ' if our lungs were. Due to the amount of alveoli, the surface area in our lungs is much larger and diffusion of gases will be much easier and faster.

Are both lungs similar in size?

Your lungs are so big in your chest that they take up most of the room in there. You have two lungs, but as your eyes or nostrils are, they are not the same size. Instead, the left lung is slightly smaller with 2 lobes while the right lung is larger with 3 lobes.

How is oxygen and carbon dioxide transported in human body?

$$\bullet$$ The oxygen and carbon dioxide transported in the human body are as follows:

$$\bullet$$ The oxygen enters into the blood from the lungs and carbon dioxide is expelled out from the blood into the lungs.

$$\bullet$$ Blood is responsible for the transportation of gases.

$$\bullet$$ Oxygen is carried by the blood and transported into the cells.

$$\bullet$$ The carbon dioxide is carried away from the cells.

Which cartilage of larynx forms "Adam's apple" in man?

The Thyroid cartilage of larynx forms Adam's apple in man (males) at puberty.

Read the following table and answer the following questions.
Sl. No. Structure Location
1. Tricuspid valve Right auriculo-ventricular aperture
2. Guard cells Epidermis of leaves
3. Glomerulus Nephron
4. Alveoli Lungs
5. Acrosome Above the head of a sperm
Name the structures which are helpful for gaseous exchange.

Alveoli are an important part of the respiratory system whose function it is to exchange oxygen and carbon dioxide molecules to and from the bloodstream. These tiny, balloon-shaped air sacs sit at the very end of the respiratory tree and are arranged in clusters throughout the lungs.
1205955_1536692_ans_8e315a17d2304a469e7be9d314524459.jpg

1205955_1536692_ans_8e315a17d2304a469e7be9d314524459.jpg

Describe respiration in human beings with a labelled diagram?

The respiratory organs of a man is a lung. Some accessory respiratory organs are
1. Nose
2. Pharynx
3. Trachea.

1. Nose: It's outermost opening. having a pair of external nares (nostrils) followed by a ridge, the nose. Air enters through nostrils. The nostrils contain hair which helps in filtering out the dirt of air. Other foreign particles i.e. germs may lodge on the moist mucous membrane of the nasal passage. The nasal passage leads internally through the internal nares into the pharynx.

2. Pharynx: From the nasal passage air enters the throat through the pharynx. Pharynx contains the openings of windpipe (trachea) called glottis and of food passage (oesophagus) called gullet. Between these two openings, there is a cartilaginous flap, the epiglottis which normally covers the gullet, except when something is swallowed: when it covers the glottis, so that chewed food only enters in the food pipe.

3. Trachea: The trachea is a pipe like structure, which is as Long as the neck of the man. Trachea is covered by a semi-circular ring like cartilage on its sides and front. At its upper part is Larynx, the sound box In the region of the chest, trachea bifurcates into bronchi. Each bronchus enters into the lung of the same side and there, it further divides into many branches-the bronchioles and fine capillaries each entering into air-sacs.

Main respiratory organ:

Lungs:
Lungs are two in number. These are enclosed in chest box. Each lung has a double wall of pleural membrane. The outer pleural membrane is in contact with muscles of ribs. Each lung is a spongy bag-like structure.
The inner pleural membrane is raised into a large number of sacs, the air sacs which increase the area for exchange of gases. These air sacs, are richly supplied with blood vessels.
Each air sac Looks like a cluster of a number of grapes and consists of a number of ballon-like swelling, called alveoli. These alveoli are thin, moist membranes and one cell thick layers. They are in close contact with the extensive capillary network. They act as a functional unit of lungs, in which the exchanges of gases takes places.

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Draw neat and labeled diagram.

Respiratory system

1745690_1827717_ans_ee09de2c856d42bc91c90b091133f9af.png

What is epiglottis?

At the start of the glottis (opening of the windpipe) is a cartilaginous flap called epiglottis. It prevents the entry of food in the windpipe and thus, facilities the breathing process to go on smoothly.

Complete the following table.
Organ system Organs Functions
1. Respiratory
2. Circulatory system

S.no.	Organ Systems	Organs	Functions
1.	Respiratory System	Nose	Traps dust particles and microbes and prevent their entry into the respiratory system.
		Pharynx	Acts as a passage for the entry of air into the windpipe.
		Windpipe	Acts as a passage through which air passes into the lungs.
		Lungs	The exchange of gases occurs in the lungs.
2.	Circulatory system	Heart	The main organ from where the circulation of blood to different body parts occurs.
		Blood vessels	The closed system of vessels which helps in the circulation of blood.

Fill in the blanks using appropriate words given in the bracket.

_________ is present between thoracic and abdominal cavity.

Diaphragm is present between thoracic and abdominal cavity.

Explain the three pathways of breakdown in living organisms.

In all organisms, glucose is first converted into pyruvate. Glucose is a 6-carbon molecule, while pyruvate is a 3-carbon molecule. This step is same in all organisms and it happens in the cytoplasm. Further breakdown of pyruvate can happen in any of the following ways:
In Yeast: In yeast, breakdown of pyruvate take place in absence of oxygen. Due to this, it is called anaerobic respiration. Pyruvate is broken down into ethanol and carbon dioxide.
In muscle cells: During strenuous physical activity, the energy demand from muscle cells suddenly increases. This is compensated by anaerobic respiration in muscle cells. In such a situation, pyruvate is broken down into lactic acid.
In mitochondria: In this case, breakdown of pyruvate takes place in presence of oxygen. Due to this, it is called aerobic respiration. Pyruvate is broken down into carbon dioxide and water. Aerobic respiration is found in most of the living beings.

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1701541_1815899_ans_3a0c2d6d34484fa891438a6e095872c6.jpg

Fill in the blanks :
Main source of sound in humans is ...........

Main source of sound in humans is Larynx

Comment on main functions of nose.

Functions of nose: are;
Provides passage for air.
Traps dust particles from air.
Moistens the air entering the respiratory system.
Gives sense of smell (olfactory receptors)

Explain the significance of trachea, bronchioles, lungs and respiratory muscles in human respiratory system.

Trachea: Trachea is composed of a muscular tube and cartilaginous rings. The rings prevent trachea from collapsing and keeps it always open for passage of air.
Bronchioles: Bronchioles are smaller branches of the bronchi present in each lung.
Lungs: Lungs are highly flexible in nature. They can expand to accommodate a large amount of air.

Respiratory Muscles: Diaphragm and intercostal muscles are the respiratory muscles. These muscles create negative pressure inside lungs to facilitate movement of air from atmosphere. These muscles also facilitate removal of air from lungs.

The voice box contains how many cartilages?

The voice box or larynx is protected by nine cartilages, 3 unpaired and 3 paired.

How does pharynx help in respiration?

Pharynx in humans, is the part of digestive system and the conducting zone of respiratory system. Pharynx constitutes nasopharynx, oropharynx and laryngopharynx. The role it plays in respiration is that it allows the air passage from nasal chamber to oropharynx via nasopharynx.

Explain the role of neural system in regulation of respiration.

The neural system plays an important role in regulation of respiration. Regulation of respiration depends on various intrinsic and extrinsic factors.
The respiratory rhythm centre is present in medulla. This is a specialized centre and is primarily responsible for the regulation of respiration.
The pneumotaxic centre is present in the pons region of the brain. It can moderate the functions of the respiratory rhythm centre. Nerve signals from pneumotaxic centre can reduce the duration of inspiration and can thus alter the respiratory rate.
A chemosensitive area is present adjacent to the rhythm centre. This is highly sensitive to $$CO_2$$ and hydrogen ions. Increase in these substances can activate this centre. Then, the chemosensitive area can give signal to the rhythm entre to make necessary adjustments so that these substances can be eliminated.
There are receptors associated with aortic arch and carotid artery. These receptors can also recognize changes in $$CO_2$$ and $$H^+ $$ concentration. Alter that, they send necessary signals to the rhythm centre so that corrective actions can be taken.
The role of oxygen is quite insignificant in the regulation of respiratory rhythm centre.

Name the important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration.

The important parts involved in creating a pressure gradient between lungs and the atmosphere during normal respiration are Diaphragm and Intercostal muscles.

Choose the odd one out in each of the following groups of four items each:

(a) Trachea, Bronchus, Alveolus, Diaphragm.
(b) Ethyl alcohol, Carbon dioxide, Starch, Oxygen absence.
(c) Diffusion, Respiratory gases, Alveoli, Capillary network.
(d) Trachea, ciliated epithelium, mucus, diffusion.
(e) Oxyhaemoglobin, carbaminohaemoglobin, Hypoxia, Carboxyheamoglobin.
(f) Hairy, Moist, Nostril, Vocal cord.

The odd one from each is as follows:

(a) Diaphragm.
(b) Starch
(c) Diffusion.
(d) Diffusion.
(e) Hypoxia.
(f) Vocal cord.

Explain the transport of $$O_2$$ and $$CO_2$$ between alveoli and tissue with diagram.

The following diagram shows the transport of $$O_2$$ and $$CO_2$$ between alveoli and tissue fluid
In alveoli, $$pO_2$$ is 104 mm Hg and $$pCO_2$$ is 40 mm Hg. In deoxygenated blood, $$pO_2$$ is 40 mmHg; which is less than the partial pressure of oxygen in alveoli. Due to this oxygen enters the blood in alveoli.
In deoxygenated blood, $$pCO_2$$ is 45 mm Hg; which is more than the partial pressure of $$CO_2$$ in alveoli. Due to this, carbon dioxide exits from tissue cells and enter the alveoli.
Once blood reaches the tissues, partial pressure of oxygen in oxygenated blood Is 95 mm Hg which is more than partial pressure of oxygen in deoxygenated blood (40 mm Hg). Hence, oxygen from blood enters the tissues.
At the tissue level, the partial pressure of carbon dioxide in deoxygenated blood is more than that in oxygenated blood. Hence, carbon dioxide exits from the tissues.

Match the lung capacities in Column I with the quantities given in Column II.
Column I Column II
A. Residual air 4500 mL
B. Vital capacity 6000 mL
C. Total lung capacity 1500 mL
D. Dead air space 150 mL

Column I	Column II
A. Residual air	1500 mL (It is the amount of air remaining in the lungs after forceful expiration)
B. Vital capacity	4500 mL (Is the total amount of air exhaled after maximum inhalation)
C. Total lung capacity	6000 mL ( It is the volume of air in the lungs after complete inspiration)
D. Dead air space	150 mL (It is the amount of ventilated air which does not take part in gaseous exchange)

Explain breathing mechanism.

The diaphragm when contracts, increases the surface area for lungs which spreads, thereby. reducing the air pressure in it. The pressure of air at the nostrils is more and hence the air flows from higher pressure area to lower pressure area i.e. lungs. This is called inhalation. When the diaphragm relaxes. it pushes the lungs thereby increasing the pressure on thern and the surface area reduces and hence the pressure of air in the lungs is more which is forced/given out from the nostrils. This is called exhalation.
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1764434_1836915_ans_29b6abe1ca944ded816d4a8dfed0acf0.jpeg

Differentiate between
(a) Inspiratory and expiratory reserve volume
(b) Vital capacity and total lung capacity
(c) Emphysema and occupational respiratory disorder

(a) Additional volume of air a person can Inspire by a forcible inspiration is called inspiratory reserve volume (IRV). Additional volume of air a person can expire by a forced expiration is called expiratory reserve volume (ERV). In a normal indivIduaL IRV is about 2500 to 3000 mL while ERV is about 1000 to 1100 mL.
(b) The maximum volume of air a person can breathe In after a forced expiration or the maximum volume of air a person can breathe out after a forced inspiration is called Vital Capacity. The total volume of air In lungs at the end of a forced Inspiration is called Total Lung Capacity.
(c) Alveoli walls are damaged in emphysema. while any other part of the respiratory system could be damaged In occupational respiratory disorder. Smoking is a major cause of emphysema. Fine particles generated during some mechanical processes are the cause of occupational respiratory disorder.

Give suitable explanations for the following:

(a) Breathing through the nose is said to be healthier than through the mouth.
(b) Why does gaseous exchange continue in the lungs even during expiration?
(c) Why does a person feel breathlessness at higher altitudes?
(d) Why do you shiver and why do your teeth chatter when it is very cold in winter?

(a) It is because the hair in the nostrils checks and prevents the large/tiny dust particles from entering the respiratory system.
(b) It is because expiration is the outcome of reverse movements of the diaphragms and ribs. As a result of the movements of the diaphragm and the ribs, the thoracic cavity shrinks and the lungs compress causing the air to be forced out of the body into the environment.
(c) A person feels breathlessness at higher altitudes because as we go up higher, the content of oxygen is lower in the air.
(d) We shiver and our teeth chatter when it is very cold in order to increase the heat production in the body. To maintain the temperature of the body constant in extremely cold conditions, the production of heat is increased through heightened metabolic rate and greater muscular activity and shivering and teeth chattering involves a lot of muscular activity.

Match the items in Column A with those in Column B.
Column A Column B
Cartilaginous Epiglottis
Large surface area Diaphragm
Breathing movements Bronchi
Voice Alveoli
Complemented air Larynx
Swallowing
Inspiratory capacity

Column A	Column B
Cartilaginous	Bronchi (bronchi are protected by C-shaped cartilage)
Large surface area	Alveoli ( small sac like structures, made of single layer of cells, that provide a large surface area for exchange of gases)
Breathing movements	Diaphragm (the diaphragm contracts and flattens to increase the volume of the thoracic cavity to aid inhalation)
Voice	Larynx (Larynx is responsible for producing sound)
Complemented air	Inspiratory air (the maximum amount of air that can be drawn into the lungs after a normal quiet expiration)
Swallowing	Epiglottis (Epiglottis prevents the entry of food into the wind pipe and thus the food moves into the food pipe)

What is the respiratory surface?

The surface which participates in the exchange of $$O_2$$ and $$CO_2$$ is called as respiratory surface.
Example: Lung alveoli.

Give suitable explanations for the following:

(i) One should breathe by nose and never by mouth.
(ii) Hands must be washed before eating food.
(iii) Eating places must be kept free of flies.

(i) It is because nostrils has hair and mucous that traps dust and microbes entering while breathing causing it to become purified and hence ensuring the respiratory passage is dust-free and germ-free.
(ii) Everything around us mostly has microbes which are not visible to us. The furniture, books, public transport etc all of these objects harbour germs which can be picked up by us once we get in touch with these objects. These germs are then transmitted to the different parts of the body, through the water we drink or through the food we eat. Hence it becomes a necessity to wash hands thoroughly before consuming food so as to stay at bay from the diseases that could be spread through these germs/vectors.
(iii) Eating places must be kept free of flies as flies carry bacteria and germs that cause various diseases.

With regard to the respiratory system and the process of respiration in man, answer the following questions:

(a) Name any two muscles that help in breathing.
(b) Briefly describe how the above mentioned muscles help in the inspiration of air.
(c) Give the overall chemical equation to represent the process of respiration in humans.
(d) What is meant by:
1. Residual air 2. Dead air space

(a) The two muscles that help in breathing are: intercostal muscles and abdominal muscles.
(b) When the intercostal muscles stretch between the ribs, they move outwards and inwards causing them to enlarge the chest cavity.
(c) The overall chemical equation for the process of respiration in humans is as given below:
Enzymes
$$C_6H_{12}O_6$$ + $$6O_2$$ → $$6CO_2$$ + $$6H_2O$$ + $$38ATP$$ + $$420Kcal$$
(d) 1. Residual Air - Even after forcibly breathing out, some air always remains in the lungs. This air is referred to as residual air. The volume of this air is 1500mL.
2. Dead air space - Some tidal air is remaining in the respiratory passages such as bronchi and trachea. Here no gas diffusion takes place. This volume is referred to as dead air space and its volume is 150mL.

Match the items in Column I with the ones most appropriate in Column II. Rewrite the matching pairs:
Column I Column II
(a) Alveoli (i) where aerobic respiration takes place.
(b) Bronchioles (ii) lined with hair.
(c) Nasal chamber (iii) Diffusion of gases.
(d) Bronchi (iv) small air tubes.
(v) An inverted Y-shaped tube.
(vi) A common passage for food and air.

Column I	Column II
(a) Alveoli	Diffusion of gases (sac like structures that exchange gases with the capillaries)
(b) Bronchioles	small air tubes ( Bronchi branch out to form bronchioles in their respective lungs)
(c) Nasal chamber	Lined with hair ( the nasal chambers are lined with hair to trap dust particles)
(d) Bronchi	An inverted Y-shaped tube (Trachea branches out into the left and right bronchi, and appears inverted 'Y' shaped)

What are the functions of the following in breathing?

(a) Ribs
(b) Diaphragm
(c) Abdominal muscles

The functions of the respective structures are as follows:
(a) Ribs - The intercostal muscles stretch between the ribs which causes its outward and inward movement which enlarges the chest cavity all around.
(b) Diaphragm - The diaphragm flattens from the dome-shaped outline to an almost horizontal plane upon contraction.
(c) Abdominal muscles - It helps to increase the size of the thoracic cavity through the motion of the diaphragm which assists in inspiration.

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion
Fill in the blanks on a similar pattern.

(a) Alveoli and _____.
(b) Mitochondria and _.
(c) Epiglottis and _.
(d) Pleura and _.
(e) Diaphragm and _.
(f) 'C' shaped cartilage rings and ____.

(a) Alveoli and gaseous diffusion.
(b) Mitochondria and power house.
(c) Epiglottis and Trachea (guard of entrance).
(d) Pleura and Lung covering.
(e) Diaphragm and Distinguishes abdominal cavity and thoracic cavity.
(f) ‘C’ shaped cartilage rings and support.

The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured. The following diagram shows a group of the lung volumes and capacities:

Study the diagram carefully and explain briefly the following:
(a) Tidal volume.
(b) Inspiratory reserve volume.
(c) Expiratory reserve volume.
(d) Vital capacity.
(e) Residual volume.

(a) Tidal volume - It is the air breathed in and out in a normal quiet breathing is known as tidal volume. The tidal volume(TV) is 500 mL.
(b) Inspiratory reserve volume - Air that can be drawn in forcibly over and above the tidal air is known as inspiratory reserve volume. It is referred to as IRV or complemental air and is 3000 mL.
(c) Expiratory reserve volume - It is the air that can be expelled out forcibly after a normal expiration. It is referred to as ERV or supplemental air and is 1000 mL.
(d) Vital capacity (VC) - It is the volume of air that can be inhaled and exhaled by maximum inspiration and expiration respectively and is about 4500mL.
(e) Residual volume (RV) - Even after forcible expiration, there is some air left in the lungs and is referred to as residual volume. It is about 1500 mL.

Write short notes on:
Respiratory volumes

Short note on respiratory volumes:

1. Tidal Volume (TV) - The amount of air expired/inspired during one breath is termed as tidal volume. It is 500 ml in human beings.
2. Inspiratory Reserve Volume (IRV] - The amount of air inspired over and above the normal inspiration. It is 2500 to 3000 ml in human beings.
3. Expiratory Reserve Volume [ERV] - The amount of air expired over and above the normal expiration. It is 1000 to 1100 ml in human beings.
4. Residual air (RV) - It is the amount of air left in both the lungs after forced expiration. It is about 1100 to 1500 ml in human beings.
5. Inspiratory Capacity (IC) - The maximum inspired air is called as IC. It includes tidal volume and IRV. It is about 3500 ml in human beings.
6. Expiratory Capacity (EC) - The maximum expired air is called as EC. It includes TV + ERV. It is about 1500 to 1600 ml. in human beings.
7. Functional Residual Capacity (FRC) - The amount of air left in the lungs after a normal expiration. It includes RV + ERV. It is about 2300 ml in human beings.
8. Vital Capacity (VC) - The amount of air expired maximum from both the lungs. It is IRV + TV + ERV. In human beings, it is 4600 ml.
9. Total Lung Capacity (TLC) - The total amount of air in both the lungs is called TLC. It is VC + RV. It is 5800 ml in human beings.

Draw a diagram of human respiratory system and label - pharynx, trachea, lungs, diaphragm and alveolar sac on it.

1950415_1943204_ans_6bd1cf075fbd4d05926120162b039604.png

What is Emphysema disease? How it can be prevented?

Emphysema:
$$\bullet$$ It is caused due to heavy smoking and air pollution. • Smoking causes continuous stimulation in the lungs which destroys the alveolar walls.
$$\bullet$$ This results in increased air space but decreases in the respiratory surface in the lungs.
$$\bullet$$ Lung elasticity is also reduced due to the increased amount of connective tissues. It causes difficulty in expiration.
$$\bullet$$ Avoiding smoking, use of antibiotics and bronchial-dilators are helpful to get relief.

What is expiratory reserve volume?

The amount of air expired over and above the normal expiration is expiratory reserve volume. It is from 1000 to 1100 ml.

Describe the human respiratory system.

Respiratory Organs of Human beings:
The respiratory passage includes the following organs -

Nostrils:
1. There is a pair of external nares which are situated obliquely at the tip of the snout. This condition is called as diaphanous.
2. Their cavities are called as fossae or nasal passage. Both the fossae remain separated by a nasal septum which is made up of mesethmoid cartilage.

Nasal Cavities:
1. The external nares open into nasal cavities which are situated dorsally to the palate. The nasal cavities open into the nasopharynx through a pair of internal nares or choanae.
2. Nasal cavities are formed as an invagination of the skin and it contains a turbinal bone which is a scrolled & porous bone,
3. The projections of the turbinal bones are called as conchae.
4. The nasal cavities remain lined by pseudo-stratified epithelium which is ciliated & glandular
5. There are Bowman's glands to secrete the mucus.
6. The nasal epithelium has olfactory receptors and it is also called as Schneiderian epithelium.
7. Functions of nasal cavities -
$$\bullet$$ It filters the inspired air
$$\bullet$$ It acts as electroreceptor
$$\bullet$$ According to new researches, it is provided with pheromones receptors.
$$\bullet$$ It maintains the temperature of inspired air by warming the air.
$$\bullet$$ It makes the inspired air moist.

Pharynx:
1. It's dorsal part is called as nasopharynx & ventral part as oro-pharynx.
2. Posteriorly, it has two openings viz.-gullet (dorsal) & glottis (ventral). The gullet leads into an oesophagus & the glottis opens into a larynx.
3. The glottis remains covered by a cartilaginous flap which is called as epiglottis. The epiglottis prevents the entry of food & water into the larynx.

Larynx:
1. It is located in the anterior end of the throat which is formed by the modification of the anterior end of the trachea.
2. It is also called a sound-producing organ.
3. Formation of larynx involves 4 cartilages which are of 3 types viz.,
$$\bullet$$ Thyroid-one largest, C-shaped & forms ventrolateral sides.
$$\bullet$$ Cricoid-one, ring-like, broad dorsally & forms base of the larynx.
$$\bullet$$ Arytenoid-Two small & from the dorsal side.
4. The anterior end of the arytenoid cartilage is knob-like and it is called as the cartilage of Santorini.
5. The larynx has two pairs of elastic vocal cords which remain stretched between the thyroid and arytenoid cartilages:
$$\bullet$$ Anterior or False vocal cords
$$\bullet$$ Inelastic & pinkish in colour.
$$\bullet$$ Posterior or True vocal cords.
Trachea or Windpipe:
1. It is a simple tube which is elastic & semi-transparent.
2. Its length in man is of 10 cm.
3. It is located in the neck ventral to the oesophagus.
4. It is lined by pseudostratified epithelium & ciliated intemally. These cilia beat constantly to force out the mucous.
5. The trachea is supported by tracheal rings made up of hyaline cartilage. These rings are C-shaped i.e. incomplete dorsally to facilitate oesophageal movements.
6. The posterior end of trachea bifurcates to form two bronchi. These bronchi are also thin-walled & elastic but they are supported by complete cartilaginous rings. Each bronchus enters into its respective lung.
Lungs:
1. Man has a pair of lungs which are situated in the thoracic cavity on both the sides of the heart.
2. The lungs are elastic, spongy, light pink, unequal & without muscles.
3. In the human being, the left lung consists of two lobes viz., left superior lobe & left inferior lobe. Whereas, the right lung includes three lobes viz: superior lobe, middle lobe & inferior lobe.
4. Each lung is bounded by two pleural membranes viz.,
$$\bullet$$ External or Parietal pleura.
$$\bullet$$ Internal or Visceral pleura.
5. Both the pleura remain closely applied to each other.
6. The space between the lung and the pleura is called a pleural cavity.
7. Each bronchus enters into the lung of own side & divide to form secondary or lobular bronchi (4 secondary bronchi in right lung & 2 secondary bronchi in the left lung).
8. Each secondary bronchus divides to form tertiary or segmental bronchi, which further divide to form intrapulmonary bronchi. The ends of intrapulmonary bronchi divide to form terminal bronchioles which further form respiratory bronchioles.
9. These bronchioles lack cartilaginous rings. Each respiratory bronchiole gives out 2 to 11 alveolar ducts. Each alveolar duct gives out small ducts, the atria. Each atrium forms small bag-like alveoli or air sacs which are made up of squamous epithelium.
10. Internally, the alveolus is lined by mucous & there is a network of blood capillaries outside. The alveoli provide more surface for the exchange of gases.
11. The diameter of a lung alveolus is 0.2 mm.
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Explain the process of inspiration.

Inspiration:
1. The entry of air into the lungs is called as inspiration or inhalation.
2. It involves:
$$\bullet$$ Contraction of the diaphragm muscles. As a result, it moves downwards i.e. the diaphragm becomes flat.
$$\bullet$$ Contraction of external intercostal muscles & relaxation of internal intercostal muscles. As a result, the ribs move outward & forward i.e. anteroventral movement of the ribs. The above changes in the factors cause an increase in the thoracic volume but the thoracic pressure is reduced. Hence, due to less pressure air enters into the lungs.
1874734_1877033_ans_f18130985a6e429ebf7aa0e5ffb999c9.jpg

1874734_1877033_ans_f18130985a6e429ebf7aa0e5ffb999c9.jpg

What is inspiratory reserve volume?

The amount of air inspired over and above the normal inspiration is inspiratory reserve volume. It is from 2500 to 3000 ml.

List three characteristics of lungs which make it an efficient respiratory surface.

The three characteristics of the lungs are:
a. Large surface area: Lungs provide a large surface area in the form of alveoli inside for the exchange of gases by diffusion. This helps in the absorption of oxygen.
b. Thin walls: The air sacs/alveoli are thin which allows the quick diffusion of the gases through it.
c. Rich in capillary supply: The alveoli are richly supplied with the capillaries that bring blood with the carbon dioxide and absorbs oxygen.

What is a tidal volume? Find out the tidal volume (approximate value) for a healthy human in an hour.

$$\textbf{Solution}$$

$$\bullet$$ Tidal volume is defined as the volume of the air which is inspired for expired during a normal respiration. The normal value of the tidal volume for an healthy human is 6000 to 8000 ml of air per minute.

$$\bullet$$ To find out the tidal volume of a healthy human per hour let us calculate the value.
$$\bullet$$ Tidal volume= 6000 to 8000mL/minute.
Tidal volume in an hour
= 6000 to 8000*60min.
=3.6*105 mL to 4.8*105 mL
$$\bullet$$ So, Tidal volume for an healthy human per hour is approximately 378-504 mL.

Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?

Each alveolus is made up of highly permeable and thin layers of squamous epithelial cells. Similarly, the blood capillaries have layers of squamous epithelial cells. Oxygen-rich air enters the body through the nose and reaches the alveoli. The deoxygenated (carbon dioxide-rich) blood from the body is brought to the heart by the veins. The heart pumps it to the lungs for oxygenation. The exchange of O$$_2$$ and CO$$_2$$ takes place between the blood capillaries surrounding the alveoli and the gases present in the alveoli.

Thus, the alveoli are the sites for gaseous exchange. The exchange of gases takes place by simple diffusion because of pressure or concentration differences. The barrier between the alveoli and the capillaries is thin and the diffusion of gases takes place from higher partial pressure to lower partial pressure. The venous blood that reaches the alveoli has the lower partial pressure of O$$_2$$ and higher partial pressure of CO$$_2$$ as compared to alveolar air. Hence, oxygen diffuses into the blood. Simultaneously, carbon dioxide diffuses out of blood and into the alveoli.

Define oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern?

The oxygen dissociation curve is a graphical representation of the percentage of saturation of oxyhaemoglobin at various partial pressures of oxygen.

In the lungs, the partial pressure of oxygen is high. Hence, haemoglobin binds to oxygen and forms oxyhaemoglobin. Tissues have a low oxygen concentration. Therefore, at the tissues, oxyhaemoglobin releases oxygen to form haemoglobin. The sigmoid shape of the dissociation curve is because of the binding of oxygen to haemoglobin. As the first oxygen molecule binds to haemoglobin, it increases the affinity for the second molecule of oxygen to bind. Subsequently, haemoglobin attracts more oxygen.

How are alveoli designed to maximize the exchange of gases?

The alveoli are thin walled and richly supplied with a network of blood vessels to facilitate exchange of gases.

Explain the mechanism of gaseous exchange at branchiole level.

The air in the bronchiole then pass into million of tiny air sacs called alveoli which are present at the end. ... Therefore, the oxygen move from the air to the blood through diffusion.

How gases exchange takes place at blood level?

Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them.

What will be the $$pO_2$$ and $$pCO_2$$ in the atmospheric air compared to those in the alveolar air?
(i) $$pO_2$$ lesser, $$pCO_2$$ higher
(ii) $$pO_2$$ higher, $$pCO_2$$ lesser
(iii) $$pO_2$$ higher, $$pCO_2$$ higher
(iv) $$pO_2$$ lesser, $$pCO_2$$ lesser.

(ii) The pO$$_2$$ (partial pressure of oxygen) will be higher in the atmospheric air compared to that in the alveolar air. The pCO$$_2$$ (partial pressure of carbon dioxide) will be lesser in the atmospheric air compared to that in the alveolar air. In atmospheric air, pO$$_2$$ is about 159 mm Hg. In alveolar air, it is about 104 mm Hg. In atmospheric air, pCO$$_2$$ is about 0.3 mm Hg. In alveolar air, it is about 40 mm Hg.

What is tidal volume? Find out the tidal volume(approximate value) for a healthy human in an hour time?

Tidal volume is the volume of air inhaled or exhaled in one breath without an extra effort. For a normal healthy adult, the tidal volume is about 500ml. Number of breaths per minute is 12−16.

Tidal volume per minute = 500 × 12 to 16 = 6000−8000ml or 6 − 8 litres.

Tidal volume per hour =6 to 8 × 60 = 360 − 480 litres.

Distinguish between IRV and ERV.

$$\textbf{Solution}$$

$$\bullet$$ IRV

It is the inspiratory Reserve volume which is the maximum volume of air that can be in held after a normal inspiration.
Its value is around 2500 -3500 mL.
$$\bullet$$ ERV
It is the expiratory reserve volume which is the maximum amount of air that can be exhaled out after a normal exhalation.
Its value is around 1000-1100 mL.

Very short answer type.
What is the normal value of tidal volume, residual volume, and total lung capacity in man?

Normal value of tidal volume is 500 ml, residual volume is 1500 ml and total lung capacity in man is 5800 ml.

Fill in the blanks with approriate words.
Alveolar $$PO_2$$ is .......... than the venous $$PO_2$$ while arterial $$PO_2$$ is .......... than the alveolar $$PO_2$$.

Alveolar PO2 is higher than the venous PO2 while arterial PO2 is lower than the alveolar PO2. It is this difference in partial pressures of O2 that causes diffusion of O2.

Fill in the blanks with appropriate words.
Pseudostratified epithelium lines the .......... tract while transitional epithelium lines the .......... tract.

Pseudostratified epithelium lines the respiratory tract while transitional epithelium lines the urinary tract. Pseudostratified epithelium is considered a special type of epithelium because of its arrangement and function. Transitional epithelium can stretch and expand so they are present in the urinary tract.

What is the maximum number of $$O_2$$ molecules which one haemoglobin molecule can carry?

Hemoglobin (Hb), which is contained in red blood cells, serves as the oxygen carrier in the blood. Each heme group contains an iron atom, and this is responsible for the binding of oxygen. The mammalian hemoglobin molecule can bind (carry) up to four oxygen molecules.

Describe oxygen-haemoglobin dissociation curve.

The oxygen dissociation curve is a graph that plots the proportion of haemoglobin in its oxygen-laden saturated form on the vertical axis against the partial pressure of oxygen on the horizontal axis. This curve is an important tool for understanding how our blood carries and releases oxygen. The curve is usually best described by a sigmoid plot. A hemoglobin molecule can bind up to four oxygen molecules in a reversible way. The shape of the curve results from the interaction of bound oxygen molecules with incoming molecules. Hemoglobin's affinity for oxygen increases as successive molecules of oxygen bind. More molecules bind as the oxygen partial pressure increases until the maximum amount that can be bound is reached. As this limit is approached, very little additional binding occurs and the curve levels out as the hemoglobin becomes saturated with oxygen. Hence the curve has a sigmoidal or S-shape.

Short / long answer type questions.
What are the requirements of a surface to be highly efficient for gaseous exchange? How has this efficiency increased from fish to mammals?

Respiratory surfaces tend to be thin and have a large surface area, structural adaptations that maximize the rate of gas exchange.
All living cells must be bathed in water to maintain their plasma membranes. The respiratory surfaces of terrestrial as well as aquatic animals are moist, and 02 and C02 diffuse across these surfaces after first dissolving in water.
The respiratory surface must supply 02 and expel C02 for the entire body. and a variety of solutions to the problem of providing a large enough surface have evolved.
An endotherm has a larger area of the respiratory surface than a similar-sized ectotherm.

Short / long answer type questions.
Differentiate between bronchus and bronchiole.

1. The bronchus is the structures which arise by the bifurcation of the windpipe before entering the lungs. Bronchioles are the small tubular extensions of repeatedly dividing secondary bronchi inside the lung.

2. Bronchus ends in bronchioles while Bronchioles end in small tubular structures called as alveolar tubes.

3. The bronchus is made up of the fibrocartilaginous layer while bronchioles are lined by smooth muscles.

4. Bronchus serves as tubes of air conductors while some of the bronchioles are air conductors and others are respiratory gas exchangers.

5. The bronchus is larger in diameter while bronchioles are smaller in diameter.

Short / long answer type questions.
How many milliliters of $$CO_2$$ are in 100 ml of deoxygenated blood at rest, and how many milliliters of $$O_2$$ are in 100 ml of oxygenated blood during strenuous exercise?

Under normal physiological conditions, every 100 ml of oxygenated blood delivers about 5 ml of O$$_2$$ to the tissues.
Under normal physiological conditions, every 100 ml of deoxygenated blood delivers about 4 ml of CO$$_2$$ to the alveoli.
During strenuous exercise, the affinity of hemoglobin towards oxygen decreases due to the lactic acid formation and increased body temperature resulting into its decreased transport than normal.

Short / long answer type questions.
Oxygen enters the blood from the alveolar air but carbon dioxide leaves the blood to enter the alveolar air. Explain.

Gaseous exchange at alveoli essentially occurs as a result of diffusion down a concentration gradient.
Inhaled oxygen is able to diffuse into the capillaries from the alveoli while carbon dioxide from the blood diffuses in the opposite direction into the alveoli. Differences in partial pressure of oxygen create a gradient that causes oxygen to move from the alveoli to the capillaries and into the tissues.
Oxygen and carbon dioxide move independently of each other.

Very short answer type.
In what way pulmonary vein is different from other veins?

Pulmonary vein carries oxygenated blood from the lungs to the heart whereas others carry deoxygenated blood.

Short / long answer type questions.
Oxygenation of blood promotes the release of $$CO_2$$ from the blood in lungs. Explain.

The release of CO$$_2$$ at the level of lungs can be explained by the Haldane effect. It describes hemoglobin’s ability to carry increased amounts of CO$$_2$$ in the deoxygenated state as opposed to the oxygenated state. Oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the removal of carbon dioxide.

Very short answer type.
Name the sites of external respiration inside lungs.

External respiration in lungs takes place in alveoli. Exchange of gases takes place by diffusion at these sites.

Differentiate between.
Inspiratory capacity and expiratory capacity

Inspiratory capacity (IC) is the total volume of air a person can inspire after a normal expiration. This includes tidal volume and inspiratory-reserve volume. Whereas expiratory capacity (EC) is the total volume of air a person expire after a normal inspiration. This includes tidal volume and expiratory reserve volume.

Very short answer type.
What is a pulse ? Where is it taken?

A wave of distention of blood due to pumping action of ventricle along the arteries; it is normally felt by pulpating radial artery near the wrist.

Short / long answer type questions.
How is oxygen transported in the blood and released in the tissues?

O2 binds reversibly to haemoglobin in blood to give oxyhaemoglobin. Haemoglobin is a red coloured pigment in the RBCs that contains iron. A maximum of 4 molecules of O2 can bind to a molecule of haemoglobin. The partial pressure of O2 is the primary factor that affects this binding. Other factors that can influence this binding are partial pressure of CO2, temperature and hydrogen ion concentration.
Oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the removal of carbon dioxide at the pulmonary capillaries of lungs. This is called as the Haldane effect.

What is respiration? Write a detail note on human respiratory organs.

Respiration is the biochemical process in which the cells of an organism obtain energy by combining oxygen and glucose, resulting in the release of carbon dioxide, water, and ATP. The main organs involved in human respiration are;

Nose: Main external opening for the respiratory system and its function is to warm, moisturize, and filter air entering the body before it reaches the lungs.

Mouth: The secondary external opening for the respiratory tract and used to supplement or replace nasal cavities function when needed

Pharynx: It is also known as the throat. Divided into nasopharynx, oropharynx, and laryngopharynx. There is a flap of elastic cartilage called epiglottis, that acts as a switch between the trachea and the esophagus and prevent food from going into the lungs.

Larynx: It is also known as the voice box and it connects laryngopharynx to the trachea. It contains special structures known as vocal folds, which allow the body to produce the sounds of speech and singing. The vocal folds are folds of mucous membrane that vibrate to produce vocal sounds.

Trachea: It connects the larynx to the bronchi. The main function of the trachea is to provide a clear airway for air to enter and exit the lungs. The epithelium lining the trachea produces mucus that traps dust and other contaminants and prevents it from reaching the lungs.

Bronchi and Bronchioles: From the trachea, the airway splits into left and right branches known as primary bronchi. They run into each lung before branching into secondary bronchi. They again split into many smaller tertiary bronchi within each lobe and they split into many smaller bronchis of less than 1mm size, and are called bronchioles and they spread throughout the lungs. The cartilages in the bronchi become more widely spaced as they are being branched. The bronchioles differ from the structure of the bronchi in that they do not contain any cartilage at all. The presence of smooth muscles and elastin allow the smaller bronchi and bronchioles to be more flexible and contractile. The main function of the bronchi and bronchioles is to carry air from the trachea into the lungs. When greater volumes of air are required by the body, such as during exercise, the smooth muscle relaxes to dilate the bronchi and bronchioles.

Lungs: The lungs are a pair of large, spongy organs found near to the thoracic region and surrounded by a pleural membrane which provides space for expansion and contraction. The interior of the lungs is made up of spongy tissues containing many capillaries and around 30 million tiny sacs known as alveoli. The alveoli are cup-shaped structures found at the end of the terminal bronchioles and surrounded by capillaries. The alveoli are lined with thin simple squamous epithelium that allows air entering the alveoli to exchange its gases with the blood passing through the capillaries.

Give a diagrammatic overview of the respiratory tree.

The respiratory tree or the tracheobronchial tree is used to describe how the air supply to the lungs is branched and distributed.

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Match the column:
Column I Column II
(a) Larynx (p) Lid of larynx
(b) Trachea (q) Air sacs
(c) Alveoli (r) Voice box
(d) Epiglottis (s) Wind pipe
(t) Common passage

The larynx is another name for the voice box. It's a tube about 2 inches long in adults. It sits above the windpipe in the neck and in front of the food pipe. The trachea, also called as the windpipe, is a cartilaginous tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. Alveoli are the air sacs present inside the lungs, these are the site of exchange of gases. The epiglottis is a flap in the throat that keeps food from entering the windpipe and the lungs. The flap is made of elastic cartilage covered with a mucous membrane, attached to the entrance of the larynx.

So the correct option is ' a-r, b-s, c-q, d-p '.

Many persons like to use asthma as an excuse for not being able to do well in sports. Try telling them about Down Fraser, who was the first women to break 60 sec in 100 m freestyle swimming. The first women to win four Olympic gold medals and the first swimmer to win the same event in three consecutive Olympics was asthmatic.
On the basis of the above passage, answer the following question.
i) Mention the qualities, which might have helped her to win medals at three Olympics consecutively.

She knew the fact that swimming was good for her asthma. This gain her interest in participating in swimming in Olympics. She trained and worked very hard in order to wind 3 gold medals in Olympics. She had that drive to win the Olympics. She was disciplined, competitive and self-confident. She was very much focused on the goals. She also had good time management and dedication to win medals at 3 Olympics consecutively.

List any three differences between tracheids and trachea

TRACHEIDS :

1) Tracheids is present in plants

2)It is a tubular, elongated, dead cell, whose main role is conduction of minerals and water

3)It has narrow lumen

TRACHEA

1) Trachea is present in the body of animals and human beings

2) Trachea is known as wind pipe, because it is a tube like structure which conducts air , and connects larynx to respiratory system. It provides air to lungs and from lungs for respiration.

3) It has wider lumen.

Name the body structure concerned with the given functional activity.
Protects the lungs from mechanical injuries.

Ribs protects the lungs from mechanical injuries

Fill in the blank on a similar pattern.
Alveoli and ________.

Bronchioles

Name the body structure concerned with the given functional activity.
Provides actual diffusion of respiratory gases in lungs.

The body structure that is the site for actual diffusion of respiratory gases are the alveoli and the capillaries.

State one function of the following.
Ciliated epithelium lining the respiratory tract.

The ciliated epithelium lining of the respiratory tract keeps the microrganisms away from body by propelling mucus up the airway. They are part of innate immunity

State one function of the following.
Pleural fluid.

pleural fluid lubricates the lung tissues and prevents the lung tissues from friction with ribs, it also lubricates and smoothens pleura, to make the gliding of pleura smooth during exhalation and inhalation.

Explain mechanism of breathing stepwise with special mention on role of various muscles involved in breathing.

Breathing consists of two phases called inhalation and exhalation.

Inhalation

In order for air to be drawn into the lungs during inhalation the volume of the thorax must increase. This is brought about due to the contraction of respiratory muscles. The diaphragm contracts and flattens and the intercostal muscles contract to pull the ribs up and out. The increased volume within the thoracic cavity lowers the pressure within the lungs with respect to the atmospheric pressure. Consequently, air is drawn into the lungs down a pressure gradient.

Exhalation

Inhalation is now complete and the next step is exhalation. The diaphragm relaxes and moves up and the relaxation of the intercostal muscles moves the ribs in and down. This has the effect of decreasing the volume within the thoracic cavity and increasing the pressure within the lungs with respect to atmospheric pressure. As a result, air moves out of the lungs down a pressure gradient.

State one function of the following.
Intercostal muscles.

Intercostal muscles depress ribs and reduces the space in the cavity of chest, thus their function is forced exhalation

Fill in the blank on a similar pattern.
'C' shaped cartilage rings and ________.

trachea is a kind of flexible tube like structure also known as wind pipe.

Struc: it is about 12 cm long and 2.5 cm wide. It lies in front of the oesophagus and extends

downwards to neck. It extends from the larynx to the middle of thoracic cavity where it

divides into the bronchi. The wall of trachea is made up of fibrous muscular tissue

supported by C – shaped cartilage rings, which are 16-20 in number. They reinforce and

provide rigidity to the tracheal wall to ensure that the trachea remains open all the

time.

Func: as trachea is internally lined with ciliated epithelium and mucous glands, so if any

foreign particle or dust particle enters, it gets trapped by the mucus and immediately

expelled out either by coughing action or may get swept towards the larynx and enter

in oesophagus where it gets expelled during defecation.

Define the following terms.
(a)Tidal volume (b) Residual volume (c) Asthma

(a)Tidal volume - Volume of air Inspired or expired under normal breathing is called tidal volume. In a normal individual. this is 500 mL; which means tidal volume is 6000 to 8000 mL per minute.
(b) Residual volume -Volume of air remaining in the lungs even after a forceful expiration. In normal individual, it is 1100 to 1200 ml.
(c)Asthma - Difficulty in breathing due to inflammation of bronchi or bronchioles. A person makes a wheezing sound while breathing during asthmatic attack

Sl. No.	Structure	Location
1.	Tricuspid valve	Right auriculo-ventricular aperture
2.	Guard cells	Epidermis of leaves
3.	Glomerulus	Nephron
4.	Alveoli	Lungs
5.	Acrosome	Above the head of a sperm

	Organ system	Organs	Functions
1.	Respiratory
2.	Circulatory system

Column I	Column II
A. Residual air	4500 mL
B. Vital capacity	6000 mL
C. Total lung capacity	1500 mL
D. Dead air space	150 mL

Column I	Column II
(a) Larynx	(p) Lid of larynx
(b) Trachea	(q) Air sacs
(c) Alveoli	(r) Voice box
(d) Epiglottis	(s) Wind pipe
	(t) Common passage

Breathing And Exchange Of Gases - Class 11 Medical Biology - Extra Questions

Mention a cause and symptom of each of the following.(i) Emphysema(ii) Renal calculi(iii) Diarrhoea

Draw a neat labelled diagram of lungs in man.

What is the role of epiglottis and diaphragm in respiration?

With regard to the respiratory system and the process of respiration in man, answer the following questions:Name the two muscles that help in breathing.

How are the human lungs best designed for the terrestrial mode of respiration?

Describe how the ventilation of the lungs will change while the athlete exercise:

What are the functions of:Larynx, trachea, bronchi and lungs in humans?

Name the structure that control breathing?

Using what you know about particle theory,explain how oxygen diffuses from an air sac into the blood.

Maximum amount of oxygen is lost from the blood in the?

What is the role of epiglottis in respiration ?

How do alveoli help in gas exchange?

Given below is an example of a certain structure and its special functional activity:Kidney and excretion.Fill in the blanks on a similar pattern:C-shaped cartilage rings and .........

State one function of pleural fluid.

How is the respiratory passage kept free of dust particles?

STRUCTURED/APPLICATION/SKILL TYPEGiven alongside is a diagrammatic sketch of a kind of part in human lungs :What do the arrows 5 & 6 indicates ?

Give suitable explanations for the following:Why does gaseous exchange continue in the lungs even during expiration?

Given below is an example of a certain structure and its special functional activity:Kidney and excretion.Fill in the blanks on a similar pattern:Alveoli and .........

STRUCTURED/APPLICATION/SKILL TYPEGiven alongside is a diagrammatic sketch of a kind of part in human lungs :Name the parts numbered 1-4.

Mention any two occupational respiratory disorders and their causes in human beings ?

Write a note on the membranous covering of the lungs?

The mucus in trachea is produced by which part?

Explain the mechanism of inspiration?

Name the process of inhalation and exhalation of air.

Why do the walls of trachea not collapse when there is less air in it?

What is the role of mouth in respiration?

Write the names of inspiratory muscles.

How are lungs designed in human beings to maximise the area for exchange of gases ?

Distinguish between inspiratory capacity and expiratory capacity.

What will be the $$pO_2$$ and $$pCO_2$$ in the atmospheric air compared to those in the alveolar air?(i) $$pO_2$$ lesser, $$pCO_2$$ higher(ii) $$pO_2$$higher, $$pCO_2$$ lesser (iii) $$pO_2$$higher, $$pCO_2$$ higher(iv) $$pO_2$$ lesser, $$pCO_2$$ leser

Distinguish between vital capacity and total lung capacity.

How is respiration regulated?

Distinguish between(a) IRV and ERV(b) Inspiratory capacity and Expiratory capacity(c) Vital capacity and total lung capacity

How are the alveoli designed to maximise the exchange of gases?

Air leaves the tiny sacs in the lungs to pass into capillaries. What modification is needed in the statement?

State the difference between the two. Nasal cavity and ear canal.

Why is the air entering the lungs dust free?

(a) Draw a labelled diagram of human respiratory system.(b) Explain the transportation of oxygen and carbon dioxide in human beings.

Explain how gaseous exchange takes place at alveoli and explain the regulation of respiration by brain.

Write the name of four respiratory disorders with symptoms.

What is respiration? Explain the process of respiration in human beings. (Figure not required)

In earthworm, haemoglobin is present in

Explain the process of inspiration and expiration under normal conditions.

Explain inspiration and expiration.

Describe any four occupational respiratory disorders.

Describe disorders of respiratory system.

Explain in brief transport of CO$$_2$$ in respiration.

Write the two functions of pericardial fluid.

How does the transportation of oxygen occur through blood?

Why does an athlete breathe faster and deeper than usual after finishing the race?

What are mucus secreting cells?

Explain the process of inspiration under normal conditions.

Diffusion of gases occurs in the alveolar region only and not in the other part of respiratory system. Why?

Describe the mechanism of respiration in man.

What is the breathing rate in man?

Discuss the transport of gases ($$O_2$$ and $$CO_2$$) in the blood.

What is partial pressure? How does it help in gaseous exchange during respiration?

What is tidal volume?

How does exchange of respiratory gases take place in the alveoli or lungs?

Choose the odd one out:Oxyhaemoglobin, Carbaminohaemoglobin, Hypoxia, Carboxyhaemoglobin

Name the body structure concerned with the given functional activity:Protects the lungs from mechanical injuries

Choose the odd one out in each of the following groups of four items each:Hairy, Moist, Nostril, Vocal cord.

Given below is an example of a certain structure and its special functional activity:Kidney and excretion.Fill in the blanks on a similar pattern:Pleura and .........

State one function of the following:Ciliated epithelium lining the respiratory tract

State one function of each of the following:Intercostal muscles

Given below is an example of a certain structure and its special functional activity:Kidney and excretion.Fill in the blanks on a similar pattern:Epiglottis and .........

Match the items in Column A with those in Column B.Column AColumn BA.Cartilaginous1.EpiglottisB.Large surface area2.DiaphragmC.Breathing movements3.BronchiD.Voice4.AlveoliE.Complemental air5.LarynxF.Swallowing6.Extra inhalation

Give suitable explanations for the following:Breathing through the nose is said to be healthier than through the mouth.

STRUCTURED/APPLICATION/SKILL TYPEThe volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.The following diagram shows a group of the lung volumes and capacities:Study the diagram carefully and explain briefly the following:Tidal volume

Starting from the nostrils, trace the path in sequence which the inspired air takes until it reaches the air sacs.

Differentiate between the following pairs on the basis of the aspect given in the brackets.Respiration and breathing (organs involved)

Fill in the blanks with approriate words.Each haemoglobin molecule can carry .......... molecules of oxygen, one in each ..........

Fill in the blanks with approriate words.Lungs are covered with the covering of ..........

Fill in the blanks with approriate words.Volume of air inspired and expired in a breath in normal respiration by man is called ..........

Fill in the blanks with appropriate words.A mammal ventilates its lungs by moving it's ........... and ..........

Fill in the blanks with approriate words.Glottis is closed during swallowing of food bolus by ..........

Fill in the blanks with approriate words.Sound is produced by vibrations of .......... located in the ..........

The metal associated with haemoglobin protein is ..........

Fill in the blanks with approriate words.In humans, the trachea is strengthened by incomplete .......... rings.

Mention a cause and symptom of each of the following.
(i) Emphysema
(ii) Renal calculi
(iii) Diarrhoea

With regard to the respiratory system and the process of respiration in man, answer the following questions:
Name the two muscles that help in breathing.

What are the functions of:
Larynx, trachea, bronchi and lungs in humans?

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
C-shaped cartilage rings and .........

STRUCTURED/APPLICATION/SKILL TYPE
Given alongside is a diagrammatic sketch of a kind of part in human lungs :
What do the arrows 5 & 6 indicates ?

Give suitable explanations for the following:
Why does gaseous exchange continue in the lungs even during expiration?

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
Alveoli and .........

STRUCTURED/APPLICATION/SKILL TYPE
Given alongside is a diagrammatic sketch of a kind of part in human lungs :
Name the parts numbered 1-4.

What will be the $$pO_2$$ and $$pCO_2$$ in the atmospheric air compared to those in the alveolar air?
(i) $$pO_2$$ lesser, $$pCO_2$$ higher
(ii) $$pO_2$$higher, $$pCO_2$$ lesser
(iii) $$pO_2$$higher, $$pCO_2$$ higher
(iv) $$pO_2$$ lesser, $$pCO_2$$ leser

Distinguish between
(a) IRV and ERV
(b) Inspiratory capacity and Expiratory capacity
(c) Vital capacity and total lung capacity

(a) Draw a labelled diagram of human respiratory system.
(b) Explain the transportation of oxygen and carbon dioxide in human beings.

Choose the odd one out:
Oxyhaemoglobin, Carbaminohaemoglobin, Hypoxia, Carboxyhaemoglobin

Name the body structure concerned with the given functional activity:
Protects the lungs from mechanical injuries

Choose the odd one out in each of the following groups of four items each:
Hairy, Moist, Nostril, Vocal cord.

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
Pleura and .........

State one function of the following:
Ciliated epithelium lining the respiratory tract

State one function of each of the following:
Intercostal muscles

Given below is an example of a certain structure and its special functional activity:
Kidney and excretion.
Fill in the blanks on a similar pattern:
Epiglottis and .........

Match the items in Column A with those in Column B.
Column A Column B
A. Cartilaginous 1. Epiglottis
B. Large surface area 2. Diaphragm
C. Breathing movements 3. Bronchi
D. Voice 4. Alveoli
E. Complemental air 5. Larynx
F. Swallowing 6. Extra inhalation

Give suitable explanations for the following:
Breathing through the nose is said to be healthier than through the mouth.

STRUCTURED/APPLICATION/SKILL TYPE
The volume of air in the lungs and the rate at which it is exchanged during inspiration and expiration was measured.
The following diagram shows a group of the lung volumes and capacities:
Study the diagram carefully and explain briefly the following:
Tidal volume

Differentiate between the following pairs on the basis of the aspect given in the brackets.
Respiration and breathing (organs involved)

Fill in the blanks with approriate words.
Each haemoglobin molecule can carry .......... molecules of oxygen, one in each ..........

Fill in the blanks with approriate words.
Lungs are covered with the covering of ..........

Fill in the blanks with approriate words.
Volume of air inspired and expired in a breath in normal respiration by man is called ..........

Fill in the blanks with appropriate words.

A mammal ventilates its lungs by moving it's ........... and ..........

Fill in the blanks with approriate words.
Glottis is closed during swallowing of food bolus by ..........

Fill in the blanks with approriate words.
Sound is produced by vibrations of .......... located in the ..........

Fill in the blanks with approriate words.
In humans, the trachea is strengthened by incomplete .......... rings.

Fill in the blanks with approriate words.
Exhalation from the lungs takes place when the size and pressure of the thoracic cavity is ..........

Fill in the blanks with approriate words.
Inflammation in the outer covering of lungs is known as ..........

Fill in the blanks with approriate words.
In lungs, the inspired air ultimately reaches to ..........

Fill in the blanks with approriate words.
Lungs lie in the thoracic cavity separated by .......... from the abdominal cavity

Fill in the blanks with approriate words.
The most characteristic feature of haemoglobin is its ability to combine reversibly with ..........

Very short answer type.
What term is used for the volume of air breathed in and out during each normal effortless respiration?

Very short answer type.
Name the structure that contains vocal cords.

Very short answer type.
Which structures are part of the conducting portion of the respiratory system?

Very short answer type.
How does the epiglottis prevent foods and liquids from entering the larynx?

Short / long answer type questions.
Draw a neat labelled diagram of human respiratory system.

Very short answer type.
How many molecules of oxygen can one haemoglobin molecule transport?

Short / long answer type questions.
Give the definition and normal values of lung volumes and lung capacities.

Short / long answer type questions.
Gaseous exchanges continue in lungs without interruption even during expiration. Explain.

Very short answer type.
Why are the right and left lungs slightly different in shape?

Short / long answer type questions.
Man can live without food for a few days but cannot live without oxygen for even a few minutes. Why?

Match the terms to these definitions.
Anaerobe, aerobe, kiss of life, spirograph, inspiration, chloride shift, tidal volume, oxygen debt tidal air.
.......... The drawing in of the breath

Match the terms to these definitions.
Anaerobe, aerobe, kiss of life, spirograph, inspiration, chloride shift, tidal volume, oxygen debt tidal air.
.......... That air which is inspired and expired during normal breathing.

Observe the following equation given and write a short note on it.
$$Hb + 4O_2 \rightarrow Hb(O_2)_4$$ (In lungs)
$$Hb(O_2)_4 \rightarrow Hb + 4O_2$$ (In tissues)

Which row in the table shows the correct percentage of oxygen in atmospheric and exhalend air ?
Atmospheric air / % Exhaled air /%
A 78 21
B 21 16
C 16 4
D 4 0.04

Fill in the blanks on a similar pattern.
a) Alveoli and ......
b) Mitochondria and .....
c) Epiglottis and .....

Fill in the blank on a similar pattern.
Pleura and ________.

With regard to the respiratory system and the process of respiration in man, answer the following question.
Name the two muscles that help in breathing.

What are the functions of the following in breathing?
Abdominal muscles.

Give appropriate biological/technical terms for the following.
The membrane that encloses the lungs.