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When diaphragm contracts,...

When diaphragm contracts,

A

the volume of the thoracic cavity increases

B

intrapulmonary pressure increases

C

the volume of the thoracic cavity decreases

D

the intrapleural pressure increases

Text Solution

AI Generated Solution

The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding Diaphragm Contraction**: When the diaphragm contracts, it flattens. This is a key action during the process of inhalation (breathing in). 2. **Effect on Thoracic Cavity Volume**: The contraction of the diaphragm increases the volume of the thoracic cavity. As the diaphragm moves downward, it creates more space in the chest for the lungs to expand. 3. **Pressure Changes in the Lungs**: As the volume of the thoracic cavity increases, the pressure inside the lungs (intrapulmonary pressure) decreases. This decrease in pressure allows air from outside to rush into the lungs. 4. **Direction of Expansion**: The expansion of the thoracic cavity occurs both downward (due to diaphragm contraction) and outward (due to the rib cage moving). This further aids in the inhalation process. 5. **Conclusion**: Therefore, when the diaphragm contracts, the correct consequence is that the volume of the thoracic cavity increases. **Answer**: When diaphragm contracts, the volume of the thoracic cavity increases. ---
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