Gas exchange in the lungs

Gas exchange in the lungs

Gas exchange in the lungs is an important process for maintaining the life of the body. It occurs due to the diffusion of oxygen and carbon dioxide between the alveoli and the blood of the pulmonary capillaries. Each of these gases moves from an area of ​​higher concentration to an area of ​​lower concentration.

The alveolar epithelium, which is extremely thin, does not offer significant resistance to the diffusion of gases. Therefore, if the concentration of oxygen in the alveoli is higher than in the blood flowing to the lungs through the pulmonary artery, oxygen diffuses from the alveoli into the capillaries. In contrast, the concentration of carbon dioxide in the blood of the pulmonary artery is under normal conditions higher than in the pulmonary alveoli, and therefore carbon dioxide diffuses from the pulmonary capillaries into the alveoli.

Alveolar cells cannot force oxygen into the blood when its concentration in the alveoli falls below a certain level. This leads to the appearance of symptoms of “altitude sickness” in people at high altitudes, where the concentration of oxygen in the air is much lower. The human body can adapt to life at high altitudes by increasing the number of red blood cells in the blood, but without an additional source of oxygen, humans cannot live much above 6,000 m.

At an altitude of approximately 11 km, the pressure is so low that even when breathing pure oxygen, a person cannot satisfy his need for this gas. Therefore, aircraft flying at such altitudes must be pressurized, and they must be equipped with pumps to maintain air pressure in the cabin equal to sea level pressure.

In the tissues of the entire body, where internal respiration occurs, oxygen passes from capillaries to cells, and carbon dioxide from cells to capillaries by diffusion. The oxygen concentration in the cells is always lower, and the carbon dioxide concentration is always higher than in the capillaries. Throughout its journey from the lungs through the blood to the tissues, oxygen moves from an area of ​​higher concentration to an area of ​​lower concentration and is finally used by the cells; Carbon dioxide moves from the cells where it is formed, through the blood to the lungs and then outward - always towards an area of ​​lower concentration. This process is vital for maintaining metabolic processes in the body's tissues.

It is important to note that gas exchange in the lungs can be impaired in various diseases, such as bronchial asthma, chronic obstructive pulmonary disease and pneumonia. These diseases can lead to a decrease in the surface of the alveolar epithelium or a deterioration in its function, which can lead to impaired diffusion of oxygen and carbon dioxide.

In conclusion, gas exchange in the lungs is an important process for maintaining the life of the body. It is carried out due to the diffusion of oxygen and carbon dioxide between the alveoli and the blood of the pulmonary capillaries. Any disruption to this process can lead to serious health consequences, so it is important to monitor the condition of your lungs and your overall health.