Boyle's law can be used to explain part of the process by which air enters and leaves the lungs during breathing. Which of the statements are true?

Question

Boyle's law can be used to explain part of the process by which air enters and leaves the lungs during breathing.

Which of the statements are true?

During inhalation, the diaphragm rises, which increases the pressure in the lungs and allows air to flow into the lungs.

A decrease in lung volume results in an increase in pressure in the lungs.

When the diaphragm lowers, the volume of the lungs decrease and the pressure in the lungs increases.

During exhalation, the diaphragm rises, which increases the pressure in the lungs and results in air being forced out of the lungs.

Answer 1

During inspiration, the diaphragm contracts and moves downward. Simultaneously, the external intercostals pull the ribs upward and outward. Both actions expand the chest cavity, reducing the pressure and allowing air to flow from higher pressure (atmosphere) to lower pressure, the lungs.

During expiration, the diaphragm relaxes and elevates, and the chest contracts, mainly due to elastic recoil. This increases the pressure in the lungs relative to the atmosphere, and air move outward.

For the statements above, the second, a decrease in lung volume results in an increase in pressure in the lungs, which is Boyle's law. Also, the fourth statement, during exhalation, the diaphragm rises, which increases the pressure in the lungs and results in air being forced out of the lungs - is partially correct. Most of the pressure increase is due to elastic recoil of the chest, which reduces the volume and increases the pressure in the lungs, forcing air out.