Which sequence correctly describes normal inspiration?

Options

  • A. Diaphragm contracts → thoracic volume increases → lung pressure decreases → air enters
  • B. Diaphragm relaxes → thoracic volume increases → lung pressure increases → air enters
  • C. Diaphragm contracts → thoracic volume decreases → lung pressure decreases → air enters
  • D. Diaphragm relaxes → thoracic volume decreases → lung pressure decreases → air enters
  • E. Diaphragm stops moving → lung pressure decreases → air enters

Correct Answer (Detailed Explanation is Below)

A. Diaphragm contracts → thoracic volume increases → lung pressure decreases → air enters

Detailed Explanation

Normal inspiration involves diaphragm contraction, increased thoracic volume, decreased intrapulmonary pressure, and inward movement of air.