Tag: respiratory organs in humans

Questions Related to respiratory organs in humans

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

Show answer
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.

Which of the following changes occur in diaphragm and intercostal muscles when expiration of air takes place? 

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  1. Internal intercostal muscles relax and diaphragm contracts

  2. External intercostal muscles and diaphragm relaxes

  3. Internal intercostal muscles contract and diaphragm relax

  4. External intercostal muscles and diaphragm contract

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Correct Option: C
Explanation:
  • When the internal intercostal muscles contract and diaphragm relax, the ribs move .downward and inward and the diaphragm becomes convex {dome shaped), 
  • thus decreasing the volume of the thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside. This will cause the air to move out (expiration).

Read the given statements and select the correct option.


Statement 1 : Mammals can eat while breathing. 

Statement 2 : Mammals have negative-pressure breathing.

evs respiration in living organisms respiration in human beings respiration and associated structures respiration in humans mechanism of respiration in animals human lungs respiratory organs in humans

  1. Both statements 1 and 2 are Correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.

Show answer
Correct Option: A
Explanation:
Mammals like humans along with birds and reptiles have negative pressure breathing. They use their mouths for both eating and breathing. Breathing requires pressure gradient. Mammals create pressure gradient using their diaphragm. The high volume and low pressure in the lung cavity results in the air to be sucked in. They cannot swallow and breathe at once. However, it is possible for them to eat while breathing.
Thus, the correct answer is option (A).

Given below is a list of different steps (i-vi) involved in respiration.
(i) Utilisation of $O _2$ by the cells for catabolic reactions
(ii) Transport of gases by the blood
(iii) Pulmonary ventilation by which atmospheric air is drawn in and $CO _2$ is released out
(iv) Release of resultant $CO _2$
(v) Diffusion of $O _2$ and $CO _2$ between blood and tissues
(vi) Diffusion of gases ($O _2$ and $CO _2$) across alveolar tissues.
Select an option which has correct sequence of all the steps.

evs respiration in living organisms respiration in human beings respiration and associated structures respiration in humans mechanism of respiration in animals human lungs respiratory organs in humans

  1. (iii), (vi), (ii), (v), (i), (iv)

  2. (iii), (vi), (i), (v), (ii), (iv)

  3. (iv), (ii), (v), (iii), (i), (vi)

  4. (iv), (vi), (ii), (v), (i), (iii)

Show answer
Correct Option: A
Explanation:

While respiration atmospheric air is drawn in a carbon dioxide is released out, diffusion of gases takes place in the alveolar tissue which is then carried by blood, then diffusion of gases take place between blood and tissues, oxygen is utilized by cells for catabolic reactions, and the resultant carbon dioxide is released from the body.

So, the correct option is '(iii), (vi), (ii), (v), (i), (iv)'.

Consider the following statements each with two blanks. 
(i)    Diaphragm contracts to help in __(1)   while the contraction of abdominal muscles helps in (2). 
(ii). Vital capacity of trained athletes is _(3)__ than that of non-athletes while the vital capacity of non-smokers is (4) than that of smokers. 
(iii) Alveolar P$O {2}$ is  _(5)  than the venous P$O {2}$ while arterial P$O _{2}$ is __(6)_ than the alveolar P$O _{2}$.
Which of the following options gives the correct fill ups for the respective blanks numbers from (1) to (6) in the above statements?

evs respiration in living organisms respiration in human beings respiration and associated structures respiration in humans mechanism of respiration in animals human lungs respiratory organs in humans

  1. (1)-expiration, (2)-inspiration (5)-higher, (6)-lower

  2. (3)-higher, (4)-lower, (5)-lower, (6)-higher

  3. (1)-inspiration, (2)-forced expiration, (3)-higher, (4)-higher

  4. (1)-expiration, (2)-forced expiration, (5)-higher, (6)-lower

Show answer
Correct Option: C
Explanation:

  (i) Diaphragm contracts to help in (1) inspiration while the contraction of abdominal muscles helps in (2) forced expiration.

(ii) Vital capacity of trained athletes is (3) higher than that of non-athletes while the vital capacity of non-smokers is (4) higher than that of smokers.

(iii) Alveolar PO2 is (5) higher than the venous PO2 while arterial PO2 is (6) lower than the alveolar PO2.

So, the correct answer is '(1)-inspiration, (2)-forced expiration, (3)-higher, (4)-higher'.