hengitysvaihto

Hengitysvaihto, also known as gas exchange, is the fundamental process by which living organisms acquire oxygen and release carbon dioxide. In mammals, this occurs primarily in the lungs, specifically within tiny air sacs called alveoli. The lungs are designed to maximize surface area for efficient exchange. Oxygen from inhaled air diffuses across the thin walls of the alveoli and into the surrounding capillaries, where it binds to hemoglobin in red blood cells. Simultaneously, carbon dioxide, a waste product of cellular metabolism, diffuses from the blood into the alveoli to be exhaled. This continuous process is crucial for cellular respiration, which provides energy for all bodily functions.

The efficiency of gas exchange is influenced by several factors, including the partial pressures of oxygen and carbon dioxide in the air and blood, the surface area available for diffusion, and the thickness of the diffusion barrier. Conditions that impair lung function, such as pneumonia or emphysema, can significantly reduce the effectiveness of this vital exchange, leading to oxygen deprivation and a buildup of carbon dioxide in the body. In aquatic organisms, gas exchange may occur through gills or directly across the skin, with adaptations to extract dissolved oxygen from water.