Multiple Choice
What happens to the diaphragm during inhalation?
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22. The Respiratory System
Introduction to Lung Physiology
Multiple Choice
Which of the following correctly describes the process of inspiration (air entering the lungs)?
A
The intercostal muscles contract, causing the rib cage to move downward and inward.
B
The diaphragm contracts and moves downward, increasing thoracic volume and decreasing pressure.
C
The diaphragm relaxes and moves upward, decreasing thoracic volume and increasing pressure.
D
The lungs contract, forcing air out of the alveoli.
Verified step by step guidance1
Understand the basic mechanics of breathing: Inspiration is the process of drawing air into the lungs, which involves changes in thoracic volume and pressure.
Identify the role of the diaphragm: During inspiration, the diaphragm contracts and moves downward. This movement is crucial for increasing the volume of the thoracic cavity.
Recognize the effect on thoracic volume: As the diaphragm contracts and moves downward, the thoracic cavity's volume increases. This is a key factor in the process of inspiration.
Understand the pressure changes: According to Boyle's Law, an increase in volume leads to a decrease in pressure. As the thoracic volume increases, the pressure inside the thoracic cavity decreases.
Relate pressure changes to air movement: The decrease in thoracic pressure creates a pressure gradient, causing air to flow into the lungs from the higher pressure outside environment, thus completing the process of inspiration.
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