When the diaphragm contracts, __________.

• A. the diaphragm becomes dome shaped
• B. exhalation occurs
• C. inhalation occurs
• D. the volume of the thoracic cavity decreases

Answer: (C)

Verified step by step guidance

1. Understand the role of the diaphragm in respiration: The diaphragm is a dome-shaped muscle located at the base of the lungs. It plays a crucial role in the process of breathing.
2. Identify the action of the diaphragm during inhalation: When the diaphragm contracts, it moves downward and flattens, increasing the volume of the thoracic cavity.
3. Relate the change in thoracic cavity volume to air movement: As the volume of the thoracic cavity increases, the pressure inside decreases, creating a pressure gradient that allows air to flow into the lungs.
4. Differentiate between inhalation and exhalation: Inhalation is the process of taking air into the lungs, while exhalation is the process of expelling air from the lungs. The contraction of the diaphragm is associated with inhalation.
5. Conclude the correct answer: Based on the understanding of diaphragm contraction and its effects, the correct answer is that inhalation occurs when the diaphragm contracts.