CBSE Questions for Class 11 Medical Biology Breathing And Exchange Of Gases Quiz 5 - MCQExams.com

Solution:

• Correct answer is option B

• Vocal cord presents in the top area of the larynx. The larynx is considerably larger in the male than in the female. 
• Hence, the Adam's apple is much more prominent in the male. At the upper end of the larynx are the vocal cords, which serve in the production of speech's .The vocal cord modulates the flow of air from the lungs and into it.

Solution:

• Correct answer is option B

• Alveoli are the primary sites of exchange of gases. Exchange of gases also occurs between blood and tissues. 
• Oxygen and carbon dioxide are exchanged at these sites by simple diffusion mainly based on pressure/ concentration gradient. 
• Solubility of the gases as well as the thickness of the membranes involved in diffusion are some important factors that can affect the rate of diffusion. 
• The diffusion membrane is made up of three major layers namely, the thin squamous epithelium of alveoli, the endothelium of the alveolar capillaries. However, its total thickness is much less than a millimetre.

Solution:

• Correct answer is option C 

• The thyroid cartilage is the largest among the nine cartilages in the larynx. 
• The larynx is considerably larger in the male than in the female; hence, the Adam's apple is much more prominent in the male.
• It is secondary sexual characters are features that help in distinguishing the male and the female body from each other. 
• Adam’s apple is basically the bony part of the thyroid cartilage present in the human.

Solution:

• Correct answer is option A

• During normal breathing, the volume of air inspired or expired is known as tidal volume. Its value is approximately 500 ml.
• Vital capacity is defined as the maximum volume of air a person can breathe in after a forceful expiration or the maximum volume of air a person can breathe out after a forceful inspiration. This includes expiratory reserve volume, tidal volume and inspiratory reserve volume. Depending on the age, sex and height of the individual, its value varies from 3400 ml to 4800 ml.
• Inspiratory reserve volume is defined as the additional or extra volume of air, a person can inspire by forceful inspiration. This volume averages 2500 ml to 3000 ml.
• Expiratory reserve volume is defined as the additional or extra volume of air, a person expires by forceful expiration. This volume averages 1000 ml to 1100 ml.

Solution

Correct answer is option A.

Explanation for correct option

• The exchange of gases can take place on the surface which is provided by the alveoli.
• The walls of the alveoli are supplied with an extensive network of blood vessels.
• Thus, lungs maximize the area for a gaseous exchange through the presence of large numbers of alveoli which are richly supplied with blood.

• Alveoli are the primary sites of the exchange of gases. Exchange of gases also occurs between blood and tissues. 
• Oxygen and carbon dioxide are exchanged in these sites by simple diffusion mainly based on pressure/ concentration gradient. 
• Pressure contributed by an individual gas in a mixture of gases is called partial pressure and represented by pO$$_2$$ for oxygen and pCO$$_2$$ for carbon dioxide. 
• Partial pressures of these two gases in the atmospheric air are 159 and 0.3 mm of Hg and in the alveoli 104 and 40 mm of Hg while in tissues the values are 40 and 45 respectively.
  
  

• The diaphragm is a part of the abdominopelvic cavity.
•  It is located below the thoracic cavity and above the pelvic cavity.
•  Its dome-shaped roof is the thoracic diaphragm, a thin sheet of muscle under the lungs, and its floor is the pelvic inlet, opening into the pelvis. Hence, the diaphragm is a dome-shaped muscle.

• The bronchi (or bronchus) are the air passages into the lungs that begin at the end of the trachea. 
• There are two bronchi, one for each lung. 
• The bronchus divides into smaller branches known as segmental bronchi, which divide again into bronchioles, Hence, Bronchi divide into bronchioles.

• The nasal cavity and the mouth meet at the pharynx, or throat, at the back of the nose and mouth. 
• From there, the air quickly enters the second part of your respiratory system, the trachea or windpipe. 

• The pharynx, or throat, is the passageway leading from the mouth and nose to the oesophagus and larynx. 
• The pharynx permits the passage of swallowed solids and liquids into the oesophagus, and conducts air to and from the trachea, or windpipe, during respiration. 
• Hence, The short tube leading from the nose is pharynx.

A.Bronchus - a passage of airway in the respiratory system that conducts air into the lungs.

B.Alveoli - any of the many tiny air sacs of the lungs which allow for rapid gaseous exchange.

C.Bronchioles - any of the minute branches into which a bronchus divides.

D.Hilum - a part of an organ where structures such as blood vessels and nerves enter the body.

So, the correct option is ‘Bronchioles’