Which process is the active movement of air into the lungs, caused by contraction of the intercostal muscles and the diaphragm?

Which process is the active movement of air into the lungs, caused by contraction of the intercostal muscles and the diaphragm?

• A. Gallbladder
• B. Epinephrine
• C. Exhalation
• D. Inhalation

Answer: (D)

Inhalation is the active movement of air into the lungs. When the diaphragm contracts, it moves downward, and the intercostal muscles contract to lift the ribs, expanding the chest cavity. This larger volume lowers the pressure inside the lungs below atmospheric pressure, so air flows in through the airways until pressures balance. Exhalation, in contrast, is typically passive at rest and involves air leaving the lungs as the chest recoils. The other options don’t relate to the act of bringing air in.

Inhalation is the active movement of air into the lungs. When the diaphragm contracts, it moves downward, and the intercostal muscles contract to lift the ribs, expanding the chest cavity. This larger volume lowers the pressure inside the lungs below atmospheric pressure, so air flows in through the airways until pressures balance. Exhalation, in contrast, is typically passive at rest and involves air leaving the lungs as the chest recoils. The other options don’t relate to the act of bringing air in.