16 **Question:**What is the volume of air expelled referred to as in respiratory physiology? A student inhales as deeply as possible and then blows the air out until they cannot exhale any more.**Options:**- ○ inspiratory reserve volume- ○ vital capacity- ○ tidal volume- ○ expiratory reserve volume- ○ minimal volume**Explanation:**This question is about identifying the correct term used to describe the volume of air expelled after a maximal inhalation followed by a maximal exhalation. Each option represents a different aspect of lung volume in respiratory physiology.

Breathing is defined as biochemical process of inhaling the oxygen and exhaling the carbon dioxide. In this process the air moves out and in the lungs, the gas exchange occurs with the internal environment. Respiration is defined as the chemical process that occurs in the living cells. The process of respiration consists of 4 process namely: pulmonary ventilation, external respiration, transport of gases and internal respiration. The maximum volume of air a person that expelled out from the lungs after a maximum inhalation is called as vital capacity (VC). The VC is equal to the sum of all inspiratory reserve volume, expiratory reserve volume and tidal volume. Thus, when a student inhales deeply and blows out the air until the student cannot exhale the air, the amount of air expelled is called as vital capacity. Hence, second option is correct. Inspiratory reserve volume (IRV) is the volume of air that is inhaled forcibly after a tidal volume. It is kept as reserve and used during deep breathing. Hence option 1 is incorrect. Tidal volume is defined as the volume of air that moves in and out during each respiratory cycle. Hence option 3 is incorrect. Expiratory reserve volume is the volume of extra air that is inhaled above the normal level and exhaled with forceful breath out. Hence option 4 is incorrect. The minimal volume of air is not a condition where a person that expelled out from the lungs after a maximum inhalation. Hence option 5 is incorrect. Thus, option 2 is correct.