Tag: respiration in humans

Questions Related to respiration in humans

Approximate normal composition of alveolar air is?

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. $14\% O _2, 6\% CO _2, 80\% N _2$

  2. $16\% O _2, 3\% CO _2, 81\% N _2$

  3. $21\% O _2, 2\% CO _2, 77\% N _2$

  4. $10\% O _2, 8\% CO _2, 82\% N _2$

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Correct Option: A

What is correct?

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. Pulmonary ventilation is equal to alveolar ventilation

  2. Alveolar ventilation is less than pulmonary ventilation

  3. Alveolar ventilation is more than pulmonary ventilation

  4. The two are variable

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Correct Option: B

Complete and balance the following equation $Na _2HPO _4+X\rightarrow Y+NaH _2PO _4$.

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. $X=NaHCO _3, Y=NaCl$

  2. $X=NaHCO _3, Y=H _2CO _3$

  3. $X=H _2CO _3, Y=NaH _2CO _3$

  4. $X=H _2CO _3, Y=NaHCO _3$

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Correct Option: D

The partial pressure of oxygen in the alveoli of lungs is?

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. Less than that of $CO _2$

  2. Equal to that in blood

  3. More than that in the blood

  4. Less than that in the blood

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Correct Option: C

Choose the correct answer from the alternatives given.
What are the tiny clusters of chambers for diffusion of gases in lungs?

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. Pleura

  2. Alveolar sacs

  3. Bronchioles

  4. Lobes

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Correct Option: B
Explanation:

The pleura are membranes that secrete a lubricating fluid, which allows free movement of the lungs against the chest wall while breathing. The alveolar sacs are sacs of many alveoli (clusters of chambers), that help exchange oxygen and carbon dioxide in the lungs. The bronchioles are the passageways by which air passes through the nose or mouth to the alveoli (air sacs) of the lungs. Each lobe of the lung has the same physiologic function, bringing oxygen into the bloodstream and removing carbon dioxide. So, the correct option is 'alveolar sacs'.

What is the approximate normal composition of alveolar air? 

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. 14% oxygen, 6% carbon dioxide, 80% nitrogen

  2. 21 % oxygen, 2% carbon dioxide, 77% nitrogen

  3. 16% oxygen, 3% carbon dioxide, 81 % nitrogen

  4. 10% oxygen, 8% carbon dioxide, 82% nitrogen

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Correct Option: A
Explanation:

The air present inside the alveoli or the alveolar air usually has a higher amount of oxygen than carbon dioxide. The approximate composition of alveolar air under normal condition is 14% oxygen, 6% carbon dioxide, and 80% nitrogen.

So, the correct answer is '14% oxygen, 6% carbon dioxide, 80% nitrogen'.


Membrane separating air in pulmonary alveoli from blood capillaries.

zoology gas exchange and smoking respiration in human beings respiration and associated structures respiration in humans respiratory organs in humans

  1. Alveolar epithelium

  2. Cardiac epithelium

  3. Endothelium of blood capillaries

  4. Both $'1'$ and $'3'$

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Correct Option: A
Explanation:
Here option (D) is the correct answer as-
Outermost Layer Of pulmonary alveolitis alveolar epithelium while that of blood capillaries is endothelium. Thus, both alveolar epithelium and endothelium of blood capillaries separate air in pulmonary alveoli from blood capillaries.

Rate and depth of

respiration shall increase when






zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. Oxygen concentration increases

  2. $CO _2$ concentration increases

  3. $HCO _3$ concentration increases

  4. $HCO _3$ concentration decreases

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Correct Option: B
Explanation:

(b) Activity of respiratory centres is directly proportional to the level of free $CO _2$ in blood.

State whether the following statements are true or false.
A normal man respires 70-80 times in a minute.

zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. True

  2. False

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Correct Option: B
Explanation:

A normal man, when resting, usually respires about 12-18 times per minute. So, the correct option is 'False'.

 A person breathing normally at rest, takes in and expels approximately half a litre of air during each respiratory cycle. This is called

zoology respiration in living organisms respiration in human beings respiration and associated structures respiration in humans

  1. inspiratory reserve volume

  2. tidal volume

  3. expiratory reserve volume

  4. vital capacity.

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Correct Option: B
Explanation:

The volume of air inspired or expired during normal breath is called tidal volume. It is about 500 mL of air in average young adult man.