The alveoli are the primary sites for gaseous exchange within the lungs, where oxygen enters the bloodstream, and carbon dioxide is expelled. This intricate process enables the body to maintain the essential balance of gases crucial for cellular respiration and overall physiological functioning.
This table now includes the percentage of water vapor and mentions the temperature characteristics of both inspired and expired air.
Component | Inspired Air (%) | Expired Air (%) |
Oxygen (O2) | 21% | 16% |
Carbon Dioxide (CO2) | 0.04% | 4% |
Nitrogen (N2) | 78% | 78% |
Water Vapor (H2O) | Variable | Saturated (100%) |
Temperature | Varies with environment | Body temperature (Approximately 37°C) |
Breathing is primarily an involuntary process, controlled by the hypothalamus in the brain. It adjusts automatically to changing internal or external conditions. During exercise, the rate of breathing increases to meet the heightened oxygen demand of the muscles, leading to a buildup of carbon dioxide in the blood, which further stimulates increased breathing. Prolonged exercise may shift to anaerobic respiration, generating lactic acid in muscles instead of carbon dioxide, causing discomfort. To repay the “oxygen debt,” deep breaths supply the extra oxygen needed, aiding recovery.
An artificial ventilator is a machine that helps when a patient struggles to breathe naturally. It delivers oxygen-rich air directly into the trachea through a tube placed in the mouth, reaching the windpipe.