MCQ on Breathing and Exchange of Gases

1. Dead space air is 
2. 1. The amount of air left in lungs after deepest expiration. 
   2. About 150 ml 
   3. Both of these 
   4. None of these

Answer: 2

The amount of air left in the lungs after the deepest expiration is Residual air. 

2. When fully saturated, one molecule of oxyhaemoglobin carries the following number of oxygen molecules. 

1. 1. Two 
   2. Three 
   3. Four 
   4. None of these 

Answer: 3

One molecule of Haemoglobin contains four molecules of Haem, so four iron atoms, for carrying for molecules of Oxygen

3.Which of the following breathing process in human is passive 

1. 1. Expiration
   2. Aspiration 
   3. Inspiration 
   4. Forced breathing 

Answer: 1

4. The amount of oxygen in tidal vol. is approximately 

1. 1. 1 litre 
   2. 3 litre 
   3. 100 ml 
   4. 500 ml 

Answer: 3

Oxygen is 21% in the air (Tidal volume = 500ml)

5. Carbon-di-oxide combines with haemoglobin 

1. 1. 200- 250 times more readily than oxygen 
   2. Twice less readily than oxygen 
   3. 20- 25 times more readily than oxygen 
   4. 100 times less readily than oxygen

Answer: 3

Diffusion of carbon-di-oxide is about 20 times faster than oxygen.

6. The chloride content of RBC will be higher than that of plasma in 

1. 1. Systemic arteries and pulmonary veins 
   2. Systemic veins and pulmonary arteries 
   3. Systemic and pulmonary arteries 
   4. Systemic and pulmonary veins 

Answer: 2

7. Byssinosis is an occupational lung disease which may occur in 

1. 1. Cement factory workers 
   2. Cotton mill workers 
   3. Sugar mill workers 
   4. Coal miners 

Answer: 2

8. The amount of air inhaled forcibly after normal breathing is called-

1. 1. Residual volume 
   2. Supplementary air 
   3. Expiratory reserve volume 
   4. None of these 

Answer: 4

This air is called Inspiratory reserve volume (IRV).

9. Adam’s apple is formed by- 

1. 1. Cricoid cartilage which is ring-shaped 
   2. Thyroid cartilage which is unpaired 
   3. Arytenoid cartilage which is paired 
   4. None of these 

Answer: 2

10. Emphysema develops mainly because of 

1. 1. Allergy or hyper sensitisation 
   2. Spasm of the smooth muscles of bronchioles 
   3. Cigarette smoking 
   4. Inflammation of the alveoli

Answer: 3

The smooth muscles of bronchioles show spasmic contraction during expiration in asthma.