Why does the diaphragm contract and flatten during inhalation?

• A. To decrease the volume of the thoracic cavity, forcing air out of the lungs.
• B. To decrease the pressure in the abdominal cavity, aiding in digestion.
• C. To increase the volume of the thoracic cavity, allowing air to flow into the lungs.
• D. To increase the pressure inside the lungs, preventing air from entering.

Answer: (C)

Verified step by step guidance

1. Understand the role of the diaphragm in the respiratory system: The diaphragm is a dome-shaped muscle located at the base of the lungs. It plays a crucial role in the process of breathing, particularly during inhalation.
2. Recognize the mechanics of inhalation: During inhalation, the diaphragm contracts and moves downward, flattening out. This movement is essential for changing the volume and pressure within the thoracic cavity.
3. Apply the principles of Boyle's Law: According to Boyle's Law, the pressure of a gas is inversely proportional to its volume. When the diaphragm contracts and the thoracic cavity volume increases, the pressure inside the cavity decreases.
4. Relate the pressure change to airflow: The decrease in pressure within the thoracic cavity creates a pressure gradient between the outside atmosphere and the inside of the lungs. Air naturally flows from an area of higher pressure (outside) to an area of lower pressure (inside the lungs), allowing inhalation to occur.
5. Conclude the function of diaphragm contraction: The contraction and flattening of the diaphragm during inhalation is primarily to increase the volume of the thoracic cavity, which decreases the internal pressure and allows air to flow into the lungs, facilitating breathing.