What role does the diaphragm play in respiration?

• A. Expands airways for easier breathing
• B. Controls the exchange of gases in alveoli
• C. Contracts to create negative pressure for inhalation
• D. Filters particles from inhaled air

Answer: (C)

The diaphragm plays a crucial role in the process of respiration by contracting, which creates negative pressure in the thoracic cavity. When the diaphragm contracts, it moves downward, increasing the volume of the chest cavity. This expansion reduces the pressure inside the lungs compared to the outside atmospheric pressure, allowing air to flow in and fill the lungs—a process known as inhalation.

In contrast, when the diaphragm relaxes, it moves back up to its dome-shaped resting position, which decreases the volume of the chest cavity and increases the pressure in the lungs, facilitating exhalation as air is pushed out. This mechanism is fundamental to the mechanics of breathing and allows for the continuous exchange of gases in the body. The diaphragm's action is vital for effective ventilation and ensures proper respiratory function.