RT Book, Section A1 Barrett, Kim E. A1 Barman, Susan M. A1 Brooks, Heddwen L. A1 Yuan, Jason X.-J. SR Print(0) ID 1159055764 T1 Respiratory Physiology: Introduction T2 Ganong's Review of Medical Physiology, 26e YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9781260122404 LK accessmedicine.mhmedical.com/content.aspx?aid=1159055764 RD 2024/03/28 AB Respiration, or the uptake of O2 and removal of CO2 from the body as a whole, is the primary goal of the lungs. At rest, a normal human breathes 12–15 times a minute. With each breath containing ∼500 mL of air, this translates to 6–8 L of air that is inspired and expired every minute. Once the air reaches the depths of the lungs in the alveoli, simple diffusion allows O2 to enter the blood in the pulmonary capillaries and CO2 to enter the alveoli, from where it can be expired. Using some basic math, on average, 250 mL of O2 enters the body per minute and 200 mL of CO2 is excreted. In addition to the O2 that enters the respiratory system, inspired air also contains a variety of particulates that must be properly filtered and/or removed to maintain lung health. Finally, although humans have a certain amount of control over breathing, most of the minute to minute function, including the fine adjustments necessary for proper lung function, are accomplished independent of voluntary control. The goal of this section is to review basic concepts that underlie important aspects of the control and outcome of breathing as well as to highlight other important functions in respiratory physiology.