THORAX ABDOMEN AND PELVIS

MEDICAL

LUNGS

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

For air to flow into the lungs, the pressure inside the alveoli must become lower than the atmospheric pressure. How does this occur?

A	By decreasing lung size
B	By coughing
C	By increasing lung size
D	None of the above

Explanation:

Detailed explanation-1: -During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. This decreases the intraalveolar pressure so that air flows into the lungs.

Detailed explanation-2: -Decreased lung dimensions lead to the alveolar pressure surpassing the atmospheric pressure, as explained by the Boyle law. As a result, air flows from the alveoli to the atmosphere until reaching a new equilibrium between the two pressures.

Detailed explanation-3: -During inhalation, the volume of the lungs increases and the pressure inside the lungs decreases below that of atmospheric pressure. This creates a pressure gradient that draws air into the lungs.

Detailed explanation-4: -During inspiration, the diaphragm and external intercostal muscles contract, causing the rib cage to expand and move outward, and expanding the thoracic cavity and lung volume. This creates a lower pressure within the lung than that of the atmosphere, causing air to be drawn into the lungs.

There is 1 question to complete.