Which term refers to the act of breathing air into the lungs?

• A. Exhalation
• B. Inhalation
• C. Ventilation
• D. Expiration

Answer: (B)

The term that refers to the act of breathing air into the lungs is inhalation. This process is a crucial aspect of respiration, where the diaphragm contracts, causing the thoracic cavity to expand. As a result, air pressure inside the lungs decreases, allowing air to flow in from outside. Inhalation is vital for delivering oxygen to the bloodstream, which is then transported to various cells throughout the body for energy production and other functions.

In contrast, exhalation is the process of breathing air out of the lungs, which involves the passive relaxation of the diaphragm and other respiratory muscles. Ventilation refers to the overall process of air movement in and out of the lungs, encompassing both inhalation and exhalation. Expiration is synonymous with exhalation, focusing specifically on the removal of air from the lungs. Understanding these terms is essential for grasping the mechanics of breathing and the respiratory system's role in maintaining vital functions in the body.