What happens during exhalation?

• A. Air is pulled into the lungs
• B. Air is pushed out of the lungs
• C. Oxygen is absorbed by the blood
• D. Carbon dioxide is filtered out

Answer: (B)

During exhalation, the primary function is to expel air from the lungs. This process occurs when the diaphragm and intercostal muscles relax, leading to a decrease in the volume of the thoracic cavity. As the thoracic volume shrinks, air pressure within the lungs becomes greater than the atmospheric pressure, causing air to be pushed out of the lungs and into the environment. This expulsion of air allows the body to eliminate carbon dioxide, a waste product of metabolism, thus maintaining proper respiratory and acid-base balances in the body.

While inhalation brings fresh air into the lungs, the focus during exhalation is on expelling carbon dioxide-rich air. This key function emphasizes the importance of breathing patterns not only for oxygen intake but also for efficient metabolic waste removal.