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CBSE Questions for Class 11 Medical Biology Breathing And Exchange Of Gases Quiz 8 - MCQExams.com
CBSE
Class 11 Medical Biology
Breathing And Exchange Of Gases
Quiz 8
Epiglottis is meant for protecting
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0%
Oesophagus from entry of air
0%
Nasal chambers from entry of food
0%
Larynx from entry of food
0%
Teeth from caries
Major part of $$CO_2$$ is transported to respiratory surface as:
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0%
Bicarbonate ions
0%
$$H_2CO_3$$
0%
$$Hb-CO_2$$
0%
Free $$CO_2$$
Explanation
About 70% of $$CO_2$$ is converted into bicarbonate ions and are transported in plasma.
Muscles attached to diaphragm contract during inspiration to make it.
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0%
Flat
0%
Dome-shaped
0%
Concave
0%
Rotate
Explanation
The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continuously, and most of the time, involuntarily.
Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. Hence, Option A is correct.
Oxygen haemoglobin dissociation curve will shift to right on decrease of.
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0%
Acidity
0%
Carbon dioxide concentration
0%
Temperature
0%
pH
Explanation
The oxygen haemoglobin dissociation curve is shifted either to right or left by various factors.
The oxyhaemoglobin curve is shifted to the right when there is high P$$CO_2$$, low P$$O_2$$, high H+ concentration (low pH) and high temperature. Hence, Option D is correct.
One reason for emphysema is?
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Liquor consumption
0%
Smoking
0%
Drug addiction
0%
Heavy exercise
Explanation
The cause of emphysema is usually long-term exposure to irritants that damage the lungs and airways. This results in breakdown of alveolar walls resulting in large spaces, that impair exchange of gases and cause breathlessness. This may occur due to Smoking. Hence, Option B is correct.
Tidal volume in human beings is?
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0%
$$1000$$ml
0%
$$1500$$ml
0%
$$500$$ml
0%
$$4.5$$litres
The amount of air that moves in and out of the lungs, with each normal inspiration and expiration is called.
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0%
Residual volume
0%
Vital capacity
0%
Tidal volume
0%
Tidal capacity
Explanation
During normal breathing, the volume of air inspired or expired is known as Tidal volume. Its value is approximately 500 ml. Hence, Option C is correct.
Pleura is double membrane sac which
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Envelops the kidneys
0%
Envelops the brain
0%
Envelops the lungs
0%
Lines the nasal passage
Explanation
There are two thin layers of tissue that protect and cushion the lungs and known as pleura.
The visceral pleura is the inner layer that is stuck so tightly to the lungs that it cannot be peeled off.
The parietal pleura is the outer layer that lines the inside of the chest wall.
The thin space between the two pleural layers is known as the pleural cavity and normally contains a small amount of pleural fluid.
So, the correct answer is option C.
In expiration, diaphragm becomes.
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Flattened
0%
Relaxed
0%
Straightened
0%
Arched/Dome-shaped
Explanation
Correct Option: B
Explanation:
The two stages of breathing are
inspiration
and
expiration
.
When the
intrapulmonary
pressure becomes lower than the atmospheric pressure, inspiration occurs.
When intrapulmonary pressure becomes higher than the atmospheric pressure, expiration takes place.
During inhalation, the diaphragm
contracts
and flattens enlarging the chest cavity.
In exhalation, the diaphragm relaxes and returns to its
domelike
shape.
Hence, in expiration, the diaphragm becomes
relaxed
.
Body tissues obtain oxygen from hemoglobin because of its dissociation in tissues caused by?
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Low oxygen concentration and high carbon dioxide concentration.
0%
Low oxygen concentration.
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Low carbon dioxide concentration.
0%
High carbon dioxide concentration.
Trachea is lined with incomplete rings of
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Fibrous cartilage
0%
Calcified cartilage
0%
Elastic cartilage
0%
Hyaline cartilage
Explanation
The trachea is also called as windpipe. It is a cartilaginous tube which connects pharynx and larynx to the lungs, allowing passage of air. The wall of the trachea is lined by C shaped incomplete cartilaginous rings to protect it from collapsing during the breathing process due to pressure exerted on its walls by the air. These incomplete rings are made up of hyaline cartilage.
So, the correct answer is 'Hyaline cartilage'.
Lungs have a large number of alveoli for __________________ .
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Having spongy texture and proper shape
0%
More surface area for diffusion of gases
0%
More space for increasing volume of inspired air
0%
More nerve suply
Explanation
B. More surface area for diffusion of gases.
Solution: The structure of the alveoli maximizes their surface area to increase gas diffusion. Alveoli are tiny sacs at the end of bronchioles, they are so tiny yet abundant that help increasing their surface area to volume ratio. Breathing ensures that the oxygen concentration in the alveoli is higher than in the capillaries so oxygen moves from the alveoli to the blood. The exchange of gases occurs between the alveoli and blood in the capillaries that supply the lungs.
Match the columns.
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
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a-r, b-s, c-q, d-p
0%
a-t, b-s, c-p, d-q
0%
a-r, b-s, c-q, d-t
0%
a-r, b-t, c-q, d-p
9 cartilages among them 3 are paired and 3 are unpaired occurs in
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Pharynx
0%
Larynx
0%
Glottis
0%
Bronchial tube
Explanation
The larynx (voice box) is a cartilaginous box which helps in sound production.
It consists of 9 cartilages among them 3 are paired and 3 are unpaired.
Vocal cords are composed of twin infoldings of mucous membrane stretched horizontally across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation.
Hence vocal cords occur in Larynx.
So, the correct answer is 'Larynx'.
Percentage of oxygen supplied by haemoglobin is?
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0%
$$97\%$$
0%
$$100\%$$
0%
$$49\%$$
0%
$$3\%$$
Explanation
A. 97%.
Solution: The percentage of oxygen supplied by haemoglobin is approx. 97 % and the rest 3% of oxygen is supplied by the plasma.
Presence of large number of alveoli around alveolar ducts opening into bronchioles in mammalian lungs is?
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Inefficient system of ventilation with little of residual air
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Inefficient system of ventilation with high percentage of residual air
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An efficient system of ventilation with no residual air
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An efficient system of ventilation with little residual air
Air is breathed through.
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Trachea $$\rightarrow$$ lungs $$\rightarrow$$ larynx $$\rightarrow$$ pharynx $$\rightarrow$$ alveoli
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Nose $$\rightarrow$$ larynx $$\rightarrow$$ pharynx $$\rightarrow$$ bronchus $$\rightarrow$$ alveoli $$\rightarrow$$ bronchioles
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Nostrils $$\rightarrow$$ pharynx $$\rightarrow$$ larynx $$\rightarrow$$ trachea $$\rightarrow$$ bronchi $$\rightarrow$$ bronchioles $$\rightarrow$$ alveoli
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Nose $$\rightarrow$$ mouth $$\rightarrow$$ lungs
Explanation
Correct Answer:
(C)
Explanation:
Air is taken inside our body from nostrils to our alveoli for gas exchange through the following sequence of pathways:
Nostrils $$\rightarrow$$ pharynx $$\rightarrow$$ larynx $$\rightarrow$$ trachea $$\rightarrow$$ bronchi $$\rightarrow$$ bronchioles $$\rightarrow$$ alveoli.
Hence,
option (C)
is the correct sequence of the breathing pathway.
Food does not enter windpipe due to structure called _________.
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Glottis
0%
Epiglottis
0%
pharynx
0%
Larynx
0%
Tonsils
Approximate normal composition of alveolar air is?
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$$14\% O_2, 6\% CO_2, 80\% N_2$$
0%
$$16\% O_2, 3\% CO_2, 81\% N_2$$
0%
$$21\% O_2, 2\% CO_2, 77\% N_2$$
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$$10\% O_2, 8\% CO_2, 82\% N_2$$
Explanation
Alveolar air represents the air located in the respiratory part of the lungs which takes part in gas exchange with the blood in the pulmonary capillaries. The air is mixed with nitrogen approximately 70-80%, oxygen around 13-14%, 5-6% carbon dioxide, and water vapour around 5-6%.
So, the correct option is A.
Which one has the smallest diameter?
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Right bronchus
0%
Left bronchus
0%
Secondary bronchiole
0%
Respiratory bronchiole
Alveoli become enlarged and damaged with reduced surface area in heavy smokers. The condition is called _______.
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0%
Silicosis
0%
Emphysema
0%
Asthma
0%
Bronchitis
Explanation
In emphysema, the inner walls of
the lungs
air sacs (alveoli)
are damaged
, causing them to eventually rupture. This creates one larger air space instead of
many small ones and reduces
the surface area
available for gas exchange, causing shortness of breath.
Emphysema mainly caused due to heavy smoking.
Silicosis is a respiratory disorder caused by breathing tiny bits of silica.
In asthma, there is an excess amount of mucus is released on the walls of the respiratory tract. It is caused due to allergic reactions.
Bronchitis is the inflammation of the bronchi.
So, the correct option is B.
Amount of air inspired or expired during normal breathing is?
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0%
$$4.5$$lt
0%
$$3.5$$lt
0%
$$1.5$$lt
0%
$$0.5$$lt
Explanation
Tidal volume (TV) measures the amount of air that is inspired and expired during a normal breath. On average, this volume is around 500ml.
So the correct option is D.
During inspiration.
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Diaphragm and external intercostal muscles relax
0%
Diaphragm and internal intercostal muscles relax
0%
Diaphragm and external intercostal muscles contract
0%
Diaphragm and internal intercostal muscles contract
Explanation
During inspiration
the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside.
As a result, air rushes in and fills the lungs.
So, the correct option is C.
In lungs, gaseous exchange occurs in ________
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0%
Bronchioles
0%
Trachea
0%
Oesophagus
0%
Alveoli
Explanation
The windpipe or trachea leads to the lungs and divides to form bronchi. In lungs, the bronchi further divide to form bronchioles. The bronchioles form the sac like structure called the alveoli. These alveoli are supplied with blood vessels. These are the sites where gaseous exchange take place.
Hence, the correct answer is 'Alveoli'
In mammals, voice is produced by _________.
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0%
Bronchus
0%
Syrinx
0%
Larynx
0%
Inhalation and exhalation
Explanation
In most mammals, sound production occurs in the vocal folds within the larynx.
The larynx, or voice box, is located in the neck above your windpipe (trachea).
Within the larynx there are two folds of elastic tissue are present along the sides and are called vocal cords.
The vocal cords vibrate as the air expelled from the lungs passes between them and produce sound.
So, the correct answer is option C.
Gases diffuse over the respiratory surface because of ______.
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$$pO_2$$ is more in alveoli than in blood
0%
$$pO_2$$ is more in blood than in tissues
0%
$$pCO_2$$ is more in alveoli than in blood
0%
$$pCO_2$$ is more in blood than in tissues
Explanation
The partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. oxygen diffuses across the respiratory membrane from the alveoli into the blood. The partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli.
So, the correct answer is option A.
Dissociation curve shifts to the right when ______________.
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$$O_2$$ concentration decreases
0%
$$CO_2$$ concentration decreases
0%
$$CO_2$$ concentration increases
0%
Chloride concentration increases
Explanation
The oxygen–hemoglobin dissociation curve, also called the oxyhemoglobin dissociation curve or oxygen dissociation curve (ODC), is a curve that plots the proportion of hemoglobin in its saturated (oxygen-laden) form on the vertical axis against the prevailing oxygen tension on the horizontal axis.
The shift of the oxygen dissociation curve to the right occurs in response to an increase in the partial pressure of carbon dioxide ($$pCO_2$$), a decrease in pH, or both.
So, the correct option is C.
Arytenoid cartilage occurs in
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0%
Larynx
0%
Nose
0%
Hyoid
0%
Sternum
Explanation
The arytenoid cartilages are a pair of small cartilages, shaped roughly like three-sided pyramids, which are located toward the rear of the larynx and play a vital role in positioning and adjusting the vocal folds during speech.
So, the correct option is is 'Larynx'.
Match the columns.
Column I
Column II
$$1$$
Tidal volume
a
$$2500-3000$$ml of air
$$2$$
Inspiratory reserve volume
b
$$1000$$ml of air
$$3$$
Expiratory reserve volume
c
$$500$$ml of air
$$4$$
Residual volume
d
$$3400-4800$$ml of air
$$5$$
Vital capacity
e
$$1200$$ml of air
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$$1-c, 2-d, 3-b, 4-a, 5-e$$
0%
$$1-c, 2-a, 3-b, 4-e, 5-d$$
0%
$$1-c, 2-a, 3-d, 4-e, 5-b$$
0%
$$1-e, 2-a, 3-b, 4-e, 5-d$$
0%
$$1-d, 2-c, 3-b, 4-a, 5-e$$
Which ones are lophodont
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Incisors and canines
0%
Canines and premolars
0%
Premolars and molars
0%
Incisors and premolars
Haemoglobin of human foetus.
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Has two protein subunits instead of four
0%
Has higher affinity of oxygen than that of the adult
0%
Has lower affinity of oxygen than that of the adult
0%
Its affinity for oxygen is the same as that of an adult
Explanation
Correct Answer:
(B) Has higher affinity of oxygen than that of the adult.
Explanation:
Fetal hemoglobin has a higher affinity for oxygen than adult ones at
all partial pressures.
This ensures that $$O_2$$ can be transferred to the fetus from the maternal blood across the placenta.
The $$PO_2$$ in fetal blood is very
low
due to its
high metabolic rate
associated with the
growth of the foetus.
This is the reason why the affinity of oxygen with hemoglobin is high in the fetal blood than that of the adult.
Hence,
option (B)
is the correct explanation.
Percentage of oxygen being carried by blood plasma is?
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0%
$$6-9\%$$
0%
$$3-6\%$$
0%
$$2-3\%$$
0%
$$1-2\%$$
Explanation
Oxygen is transported in the blood in two ways: A small amount of oxygen (1-2%)
Is carried in the plasma as a dissolved gas. Most oxygen (98-99%)
carried in the blood is bound to the protein hemoglobin in red blood cells.
So the correct answer is option D.
Two fibro-elastic strands of larynx extend between _________.
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0%
Thyroid and cricoid
0%
Thyroid and arytenoid cartilages
0%
Cricoid and tracheal cartilaginous ring
0%
Santorini and thyroid cartilages
Match the columns.
Column I
Column II
(a)
Asthma
p
Recurring bronchitis
(b)
Emphysema
q
Accumulation WBCs in alveoli
(c)
Pneumonia
r
Allergy
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0%
a-r, b-p, c-q
0%
a-q, b-, c-r
0%
a-r, b-q, c-p
0%
a-q, b-r, c-p
With decrease in temperature oxyhaemoglobin curve will become
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0%
Straight
0%
More steep
0%
Parabola
0%
All the above
Explanation
A decrease in temperature favors the affinity of hemoglobin for oxygen so more oxygen and hemoglobin binding will take place and the graph will become steeper.
Thus the correct answer is 'More step'.
Emphysema is characterized by ________.
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0%
Inflation of alveoli
0%
Pulmonary haemorrhage
0%
Increased number of air sacs
0%
Infection of
Mycobacterium
Explanation
Emphysema is a respiratory disorder.
In emphysema, the air sacs in the lungs (alveoli) are damaged.
Over time, the inner walls of the air sacs weaken and rupture, creating larger air spaces instead of many small ones, which cause inflammation of the alveoli.
Emphysema is mainly caused by cigarette smoking.
So the correct answer is option A.
Choose the correct labelling for the diagram.
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a - Larynx, b - Parathyroid, c - Tracheal cartilage, d - Trachea
0%
a - Nasopharynx, b - Thyroid, c - Tracheal cartilage, d - Trachea
0%
a - Trachea, b - Thyroid, c - Bronchiole, d - Tracheal cartilage
0%
a - Epiglottis, b - Parathyroid, c - Trachea, d - Tracheal cartilage
In which disease, due to flattening of tracheal vessels, alveoli are deprived of oxygen?
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0%
Penumonia
0%
Emphysema
0%
Asthma
0%
Bronchitis
Explanation
Asthma is a respiratory disease that is also caused by inflammation of the airways and flattening of the tracheal vessel. It makes breathing hard and alveoli are deprived of oxygen.
So the correct answer is option is C.
According to Boyle's law, the product of pressure and volume is constant, hence.
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0%
If volume of lung is increased, the pressure decreases proportionately
0%
If volume of lung is increased, the pressure also increases proportionately
0%
If volume of lungs is increased, the pressure decreases disproportionately
0%
If volume of lungs is increased, the pressure remains the same
Which can bind several hundred times more strongly to haemoglobin than oxygen?
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0%
$$CO_2$$
0%
CO
0%
$$H_2CO_3$$
0%
$$SO_2$$
Explanation
CO can bind several hundred times (200-250 times) more strongly to haemoglobin than Oxygen.
So, the correct answer is '
CO'
Which is related to oxygen toxicity?
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Blood poisoning
0%
Collapsing of alveolar wall
0%
Failure of ventilation
0%
Both A and B
Bilirubin is formed by breakdown product of
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0%
Haemoglobin
0%
Haemocyanin
0%
Haemopoietin
0%
Haematin
Oxygen carrying capacity of blood is reduced by.
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0%
$$CO_2$$
0%
CO
0%
$$SO_2$$
0%
$$O_3$$
Sometimes RBCs form a pile or stack known as
Report Question
0%
Lacuna
0%
Islet
0%
Rouleaux
0%
Canaliculi.
Explanation
Rouleaux
(singular is
rouleau
) are stacks or aggregations of Red blood cells
(RBCs) that form because of the unique discoid
shape of the cells in vertebrates
.
The flat surface of the discoid RBCs gives them a large surface area to make contact with and stick to each other; thus forming a rouleau.
They occur when the plasma protein
concentration is high.
Therefore, Option C is the correct answer.
What is the value of pO$$_2$$ in alveoli and tissues respectively?
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0%
$$104$$mm Hg, $$40$$mm Hg
0%
$$44$$mm Hg, $$104$$mm Hg
0%
$$45$$mm Hg, $$0.3$$mm Hg
0%
$$159$$mm Hg, $$40$$mm Hg
Explanation
The partial pressure of oxygen in the alveoli of the lungs is approximately 104 mm Hg while within the tissues is 40mm Hg.
So, the correct answer is option A.
Oxyhaemoglobin is converted into haemoglobin during the internal respiration because
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0%
An enzyme splits oxyhaemoglobin
0%
Oxygen tension in tissues is less than capillary blood reaching tissues
0%
CO$$_2$$ tension is low in blood that reaches tissues
0%
Oxyhaemoglobin is unstable
Explanation
A small amount of oxygen does dissolve in the blood and is transported in the bloodstream, but it is only about 1.5% of the total amount. The majority of oxygen molecules are carried from the lungs to the body’s tissues by a specialized transport system, which relies on the erythrocyte—the red blood cell. Heme is the portion
of hemoglobin that contains iron, and it is heme that binds oxygen. One hemoglobin molecule contains iron-containing heme molecules, and because of this, each hemoglobin molecule is capable of carrying up to four molecules of oxygen. As oxygen diffuses across the respiratory membrane from the alveolus to the capillary, it also diffuses into the red blood cell and is bound by hemoglobin. The following reversible chemical reaction describes the production of the final product,
oxyhemoglobin
(Hb–O
2
), which is formed when oxygen binds to hemoglobin.
So, the correct option is 'Oxygen tension in tissues is less than capillary blood reaching tissues'.
A respiratory disease is?
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0%
Cancer
0%
Arthritis
0%
Polio
0%
Asthma
Wind pipe arises from _________.
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0%
Larynx
0%
Nasopharynx
0%
Oropharynx
0%
Laryngopharynx
Explanation
The trachea or windpipe is the tube in air-breathing vertebrates that conducts air from the throat to bronchi. It originates
at the caudal end of the larynx and extends into the thoracic cavity, bifurcating distally at the carina to form the primary, extrapulmonary, airways of the lungs.
So the correct answer is option A.
A person starts coughing suddenly while swallowing some food. It could be due to improper movement of:
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0%
Neck
0%
Diaphragm
0%
Tongue
0%
Epiglottis
Explanation
If a person suddenly starts coughing while swallowing food, it is due to improper movement of epiglottis. If the glottis is not properly closed some food can enter respiratory tract resulting in coughing.
So, the correct answer is '
Epiglottis'
Congestion of lungs is one of the main symptoms in.
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0%
Hypertension
0%
Angina
0%
Heart failure
0%
Coronary artery disease
0%
Atherosclerosis
Explanation
Pulmonary congestion is most frequently caused by heart failure, which results in stagnation of blood in pulmonary vessels, leading to edema and egression of erythrocytes into the alveolar spaces.
So, the correct answer is '
Heart failure'
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