What happens during inhalation in terms of air pressure?

What happens during inhalation in terms of air pressure?

• A. Pressure in the lungs rises above atmospheric pressure
• B. Pressure in the lungs drops below atmospheric pressure
• C. Pressure in the pleura is equal to atmospheric pressure
• D. Pressure in the lungs remains constant

Answer: (B)

During inhalation, the diaphragm and intercostal muscles contract, expanding the thoracic cavity. This expansion causes the volume of the lungs to increase, leading to a decrease in pressure within the lungs. As the internal lung pressure drops below the atmospheric pressure, air from outside the body flows into the lungs in an attempt to equalize the pressure. This process is essential for the mechanics of breathing, allowing oxygen-rich air to enter the respiratory system effectively.

The concept of pressure differentials is fundamental to understanding how air moves in and out of the lungs. When the pressure inside the lungs is lower than that of the surrounding environment (atmospheric pressure), air will naturally flow into the lungs to equalize the pressures.