Exchange of gases occurs across the respiratory membrane. Which of the following would increase the rate of diffusion of a gas across the respiratory membrane?
1. | respiratory membrane becomes thicker. |
2. | surface area of the respiratory membrane decreases. |
3. | partial pressure difference of the gas across the respiratory membrane increases. |
4. | diffusion coefficient of the gas decreases. |
When compared with carbon dioxide, the partial pressure of oxygen in the air and its solubility in water is respectively:
1. lower, lower | 2. lower, higher |
3. greater, lower | 4. greater, higher |
Name the cavities in which the lungs are located:
1. pleural and abdominal cavities.
2. pericardial and thoracic cavities.
3. pleural and thoracic cavities.
4. pleural and pericardial cavities.
What is the partial pressure of oxygen and carbon dioxide respectively in the venous blood leaving the tissues [in mm of Hg]?
1. 104, 40 | 2. 95, 40 |
3. 40, 45 | 4. 20, 46 |
A minimal amount of pleural fluid present in the pleural cavity:
1. | provides a medium for the exchange of respiratory gases |
2. | reduces friction between the visceral and parietal pleurae |
3. | provides lubrication for movements of the diaphragm |
4. | permits the exchange of electrolytes during respiration |
When the diaphragm or external intercostal muscles contract, intrapulmonary pressure should
1. | increase | 2. | decrease |
3. | remain constant | 4. | equal atmospheric pressure |
Air conditioning – warming, humidifying and filtering of the air, is the function performed by:
1. | oral cavity | 2. | nasal cavity |
3. | pharynx | 4. | larynx |
During deglutition, the food is prevented from entering into the larynx by the cartilaginous:
1. epiglottis | 2. glottis |
3. aryepiglottic fold | 4. laryngeal prominence |
What is true about RBCs in humans?
1. | They carry about 20-25 percent of |
2. | They transport 99.5 percent of |
3. | They transport about 80 percent oxygen only and the rest 20 percent of it is transported in a dissolved state in blood plasma |
4. | They do not carry at all |
Oxygen binding to haemoglobin in blood is
1. | directly proportional to the concentration of CO2 in the medium |
2. | inversely proportional to the concentration of CO2 in the medium |
3. | directly proportional to the concentration of CO in the medium |
4. | independent of the concentration of CO in the medium |