Lungs are made up of air-filled sacs, the alveoli. They do not collapse even after forceful expiration, because of

1. Residual Volume (RV)

2. Inspiratory Reserve Volume (IRV)

3. Tidal Volume (TV)

4. Expiratory Reserve Volume (ERV)

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

(1) equal to that in the blood

(2) more than that in the blood

(3) less than that in the blood

(4) less than that of carbon dioxide

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because

(1) there is a negative pressure in the lungs

(2) there is a negative intrapleural pressure pulling at the lung walls

(3) there is a positive intrapleural pressure

(4) pressure in the lungs in higher than the atmospheric pressure

Reduction in pH of blood will

(1) reduce the blood supply to the brain

(2) decrease the affinity of hemoglobin with oxygen

(3) release bicarbonate ions by the liver

(4) reduce the rate of heart beat

Name the chronic respiratory disorder caused mainly by cigarette smoking

1. asthma

2. respiratofy acidosis

3. respiratory alkalosis

4. emphysema

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

1.  equal to that in the blood

2.  more than that in the blood

3.  less than that in the blood

4.  less than that of carbon dioxide

Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because

1.  there is a negative pressure in the lungs

2.  there is a negative intrapleural pressure pulling at the lung walls

3.  there is a positive intrapleural pressure

4.  pressure in the lungs is higher than the atmospheric pressure