Identify the incorrect step in the process of air being expelled from ...
During expiration, the relaxation of the diaphragm and inter-costal muscles leads to a decrease in thoracic volume and pulmonary volume. This reduction in volume causes an increase in intra-pulmonary pressure, slightly above atmospheric pressure, resulting in the expulsion of air from the lungs. This process allows for the removal of carbon dioxide from the body and is essential for maintaining proper respiratory function.
Identify the incorrect step in the process of air being expelled from ...
Decrease in thoracic volume:
- During expiration, the expulsion of air from the lungs occurs through a decrease in thoracic volume.
- This decrease in volume is primarily due to the relaxation of the diaphragm and intercostal muscles.
Relaxation of the diaphragm and intercostal muscles:
- The diaphragm, a dome-shaped muscle located at the base of the lungs, relaxes during expiration.
- This relaxation causes the diaphragm to move upwards into a more dome-like shape, reducing the volume of the thoracic cavity.
- Additionally, the intercostal muscles, located between the ribs, also relax, allowing the rib cage to move downward and inward.
Mechanism of expulsion:
- As the diaphragm and intercostal muscles relax, the volume of the thoracic cavity decreases.
- This decrease in volume leads to an increase in intra-pulmonary pressure.
- The increase in pressure causes air to flow out of the lungs, as air moves from an area of high pressure (lungs) to an area of low pressure (outside the body).
Conclusion:
- In summary, the expulsion of air from the lungs during expiration occurs due to a decrease in thoracic volume, which is facilitated by the relaxation of the diaphragm and intercostal muscles.
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