What occurs during exhalation in the respiratory process?

What occurs during exhalation in the respiratory process?

• A. Air moves into the lungs from the atmosphere
• B. Lung pressure drops below atmospheric pressure
• C. Air moves out of the lungs as pressure rises
• D. Gas exchange occurs predominantly at this stage

Answer: (C)

During exhalation, the primary process involves the movement of air out of the lungs, which occurs because the pressure within the lungs rises above atmospheric pressure. As the diaphragm and intercostal muscles relax, the thoracic cavity decreases in volume, which increases the intra-pulmonary pressure. This higher pressure forces the air to exit the lungs and be expelled into the atmosphere.

Understanding this process is crucial because it highlights the mechanics of breathing, where pressure gradients dictate the flow of air. The relationship between lung volume and pressure is fundamental to respiratory physiology, making option C the correct choice.