- 1(current)
Q. No.Consider the following two statements:
| I: | The lungs are situated in the thoracic chamber which is anatomically an air-tight chamber. |
| II: | This arrangement is essential as we cannot directly alter the thoracic volume. |
| 1. | Both I and II are correct and II correctly explains I |
| 2. | Both I and II are correct but II does not explain I |
| 3. | I is correct and II is incorrect |
| 4. | Both I and II are incorrect |
It is necessary that lungs must be present in anatomically air-tight chamber because:
1. we cannot directly alter the pulmonary volume
2. our lungs are not made of any elastic tissue
3. the pleural cavity always has a positive pressure with respect to pulmonary pressure
4. the partial pressure of oxygen in atmosphere is less than that in the alveoli
During expiration, the diaphragm and external intercostal muscles are:
1. contracted
2. relaxed
3. flexed
4. both relaxed (diaphragm) and flexed (intercostal muscles)
The figure shows the events happening during the inhalation and exhalation phases of pulmonary ventilation. Read the two given statements carefully.
| I: | A shows the inhalation phase brought about by the contraction of diaphragm that increases the volume of thorax in antero-posterior axis and by the contraction of external intercostal muscle that increases the volume of thorax in dorso-ventral axis. |
| II: | B shows the exhalation phase brought about by the relaxation of diaphragm that decreases the volume of thorax in antero-posterior axis and by the contraction of internal intercostal muscle that decreases the volume of thorax in dorso-ventral axis. |
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
The external intercostal muscles and the diaphragm contract:
1. during inhalation
2. during exhalation
3. during both inhalation and exhalation
4. during neither inhalation nor exhalation.
When the diaphragm or external intercostal muscles contract, intrapulmonary pressure should
| 1. | increase | 2. | decrease |
| 3. | remain constant | 4. | equal atmospheric pressure |
In inspiration during pulmonary ventilation the correct order of the given events is:
a. air flows into the lungs
b. alveolar volume increases
c. thoracic volume increases
d. pleural pressure decreases
e. alveolar pressure decreases
| 1. | a, b, c, d, e | 2. | b, e, a, c, d |
| 3. | c, d, b, e, a | 4. | d, e, b, a, c |
The volume of thoracic chamber in the antero-posterior axis can be increased by:
1. Contraction of diaphragm
2. Relaxation of diaphragm
3. Contraction of external intercostals
4. Contraction of internal intercostals
| I: | Relaxation of the diaphragm and the intercostal muscles causes the expulsion of air from the lungs. |
| II: | Relaxation of the diaphragm and the intercostal muscles increases the volume of thoracic chamber in the antero-posterior axis. |
2. Both I and II are correct but II does not explain I
3. I is correct but II is incorrect
4. I is incorrect but II is correct
Exhalation will be brought about by the contraction of:
| 1. Diaphragm | 2. External intercostals |
| 3. Internal intercostals | 4. Deltoid |
- 1(current)
Q. No.
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