Respiratory Physiology Practice MCQs

Question 1

MCQ: The majority of CO2 transport in the blood occurs as:

Answer 1

HCO3-

Question 2

The Bohr effect is characterised by a right shift in the lungs BECAUSE Hb has a high affinity for oxygen at low PCO2.

Answer 2

D)The first statement is incorrect, the second is correct

Question 3

Which one of the following is NOT correct regarding the respiratory control centre?
A. Dorsal respiratory group (DRG) consists of only inspiratory neurons and produce only inspiratory stimulus
B. Pre-Botzinger complex is the respiratory rhythm generator.
C. Sectioning the brain stem at the level of low medulla leads to respiratory arrest.
D. Ventral respiratory group (VRG) neurons produce inspiratory and expiratory stimulus at rest.

Answer 3

D. Ventral respiratory group (VRG) neurons produce inspiratory and expiratory stimulus at rest.
- only during exercise NOT rest

Question 4

Arterial PCO2 decreases during strenuous (intense) exercise (BECAUSE) strenuous (intense) exercise generates and releases lactic acid into the blood.

Answer 4

B) Both the statements are correct but not causally related

Question 5

Which ONE of the following is the key for achieving stable balance between the breaths?
A. Transpulmonary pressure should always be positive
B. Intrapleural pressure should become positive at the end of inspiration
C. Alveoli should expand in size to its maximum during inspiration
D. Chest wall should maintain its elastic recoiling in between the breath

Answer 5

A. Transpulmonary pressure should always be positive

Question 6

Surfactant:
A. lowers surface tension at the fluid-gas interface of the alveoli
B. stabilizes the smaller alveoli, thereby preventing them from collapsing due to high pressure.
C.is a mixture of both lipids and protein, but its major component is protein.
D. Only A and B are correct.

Answer 6

D. Only A and B are correct.

Question 7

Which of the following statements are correct regarding airway resistance?
(i). Airflow velocity decreases as the size of the airways become smaller, hence the highest resistance is seen in the respiratory bronchioles.
(ii) Air way resistance is inversely related to the fourth power of the radius (r4).
(iii). In healthy individuals, inspiration reduces the airway resistance due to an increase in the transpulmonary pressure (Ptp).
(iv). Asthma increases airway resistance.
A. (i), (iii) and (iv) are correct.
B. (ii), (iii), (iv) are correct.
C.(i), (ii) and (iv) are correct.
D. only (ii) and (iii) are correct.

Answer 7

B. (ii), (iii), (iv) are correct.
- highest resistance at bronchi smaller CA

Question 8

FEV1/FVC ratio does not decrease below 70% in restrictive lung disease BECAUSE restrictive lung disease does not affect the airway resistance

Answer 8

A) Both statements are true, and are causally related

Question 9

The movement of oxygen by diffusion between the alveoli and the pulmonary capillary blood is:
A. inversely related to the area of the alveolar membrane.
B. inversely related to the diffusion constant
C. directly related to the thickness of the alveolar membrane.
D. proportional to the partial pressure gradient between air-blood barrier.

Answer 9

D. proportional to the partial pressure gradient between air-blood barrier.