Asked in Premeth past paper pool — BiologyModerate

During inhalation, the pressure and volume of thoracic cavity

Correct answer: C. Pressure decreases, volume increases

  • A. Both pressure and volume increase
  • B. Pressure increases, volume decreases
  • C. Pressure decreases, volume increases
  • D. Both pressure and volume decrease

Explanation

During inhalation, the diaphragm contracts and moves downward, and the intercostal muscles contract, expanding the rib cage. This increases the volume of the thoracic cavity, which in turn decreases the pressure inside it relative to the atmospheric pressure. As a result, air flows into the lungs. The correct answer is that pressure decreases while volume increases. The other options describe scenarios that do not occur during inhalation, as they would not facilitate the movement of air into the lungs.

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