A: Pneumotaxic centre controls the rate of respiration.
R: Primarily, it controls the switch-off point of inspiration.
A: Asthmatic patients use bronchiodilator drugs as well as inhalers for symptomatic relief.
R: Asthma is characterized by the spasm of smooth muscles in bronchioles' wall due to allergen.
A: Major part of carbon dioxide is transported in the form of sodium bicarbonate.
R: 0.3 ml of carbon dioxide is transported per 100 ml of blood in a dissolved state in plasma of blood.
Only 7% of CO2 is transported in a dissolved state in plasma of blood.
A: In cockroach, inspiration is a passive process.
R: Expansion of the abdominal cavity allows the space of expansion of the tracheal trunk. As a result, air enters through the spiracle.
A: Diffusion of carbon dioxide is 20 times faster than oxygen.
R: It is due to the difference in partial pressure as well as solubility of diffusing gases.
Solubility of CO2 is 20 times faster than O2.
A: The passage starting with the external nostrils up to the terminal bronchiole constitute the respiratory part.
R: The respiratory part transports the air to the alveoli, clears it from the foreign material, humidified and brings the air to body temperature.
A: Normal expiration during quiet breathing, unlike inspiration, is a passive process because no muscular contractions are involved.
R: Normal expiration results from the elastic recoil of the chest wall and lungs.
A: Human blood always contains more CO2 than blood oxygen.
R: Solubility coefficient of CO2 is more than O2.
In 100 ml oxygenated blood, the amount of O2 is about 20 ml while CO2 is about 48 ml.
A: When a person starts doing exercise, rate and depth of breathing increase even before changes in pO2, pCO2 or H+ concentration.
R: The main stimulus for these quick changes is input from the proprioreceptors, which monitor joints and muscles' movements.
A: Emphysema is a chronic obstructive disease of the lung, causing irreversible distension and loss of alveoli elasticity.
R: Emphysema is preventable if chronic exposure to smoke (cigarette and others) and pollutants is avoided.
A: 100 ml of venous blood has 14.4 ml of O2, i.e. it is still 75% saturated with oxygen in normal condition.
R: About 4.6 ml of O2, i.e. 25% diffuses from arterial blood into the tissue during exercise.
Because during normal conditions, oxygen demand in tissue is low.