| Statement I: | The partial pressure of oxygen is equal in alveoli and oxygenated blood. |
| Statement II: | The partial pressure of carbon dioxide is equal in alveoli and deoxygenated blood. |
| Assertion (A): | O2 gets bound to haemoglobin in the lung surface and gets dissociated at the tissues. |
| Reason (R): | In the alveoli, there is high pO2, low pCO2, lesser H+ concentration and lower temperature whereas in the tissues, low pO2, high pCO2, high H+ concentration and higher temperature exist. |
| 1. | Both (A) and (R) are True and (R) correctly explains (A) |
| 2. | Both (A) and (R) are True but (R) does not correctly explain (A) |
| 3. | (A) is True but (R) is False |
| 4. | (A) is False but (R) is True |
| 1. | 95 | 2. | 75 |
| 3. | 27 | 4. | 15 |
| a. | pCO2 is high and pO2 is low |
| b. | dissociation of CO2 from carbamino-haemoglobin takes place |
| c. | pCO2 is low and pO2 is high |
| d. | more binding of carbon dioxide to haemoglobin occurs |
| I: | A chemosensitive area is situated adjacent to the rhythm centre which is highly sensitive to CO2 and hydrogen ions. |
| II: | Receptors associated with aortic arch and carotid artery can recognise changes in O2 concentration and send necessary signals to the rhythm centre for remedial actions. |
| III: | The role of oxygen in the regulation of respiratory rhythm is most significant. |
| 1. | Emphysema | 2. | Asthma |
| 3. | Tuberculosis | 4. | Common cold |
| Statement I: | The alveoli have ciliated cells in them to help expel dust particles that make it this far down into the respiratory tract. |
| Statement II: | Gas exchange between the lungs and the blood, and between the blood and tissue fluid, is an active transport process. |
| Statement I: | Intrapulmonary pressure must be greater than atmospheric pressure for air to enter the lungs. |
| Statement II: | Intrapulmonary pressure must be lower than atmospheric pressure for air to be exhaled out of the lungs. |