Gas exchange

Gas exchange is a set of processes ensuring the transfer of oxygen from the external environment in the tissues of the living organism, and carbon dioxide from the tissues into the environment.
Moving gas (light - blood - tissue) is carried out under influence of a difference of partial pressures and stresses of these gases in each of the environments of an organism.
The partial pressure of oxygen in the air, filling the alveoli of the lungs, about 100 mm RT. century, and its voltage in venous blood flowing to the lungs, about 40 mm RT. senior Due to the differential pressure oxygen from the alveoli are sent in the blood, where it binds with hemoglobin of the red blood cells.
The partial pressure of carbon dioxide in the alveolar air is 40 mm RT. century, and its voltage flowing to the lungs venous blood - 48 mm RT. senior Due to the differential pressure carbon dioxide goes into the alveoli.
In arterial blood flowing to the tissues, the pressure of oxygen is higher than in the tissues, and the pressure of carbon dioxide, by contrast, is much lower. Consequently, oxygen moves from the blood into the tissues and is included in the cycle of metabolic processes, and carbon dioxide in excess contained in the tissues, passes into the blood and then transferred to the lungs. The process of gas exchange occurs continuously as long as there is a difference of partial pressures and stresses of the gases in each of the environments that are involved in gas exchange decisive factor in the continuity of gas exchange, is the constancy of the gaseous composition of the alveolar air.
The amount of gas exchange is the intensity of oxidative processes in tissues. To estimate the intensity of gas exchange determines the amount of oxygen used by the body over time, and the amount of carbon dioxide that is allocated by the body during this time. These data exchange used to determine the heat of the body by indirect calorimetry (see).
About the level of gas exchange can be judged by the value of minute ventilation (see the Breath). During quiet breathing through the lungs is about 8000 ml of air in 1 min At the physical and emotional stress, various diseases accompanied by increased oxidative processes in tissues, such as an overactive thyroid gland, lung ventilation increases. Gas exchange between tissues and blood, blood and the lungs, the lungs and the external environment can largely be violated for different diseases of the lungs, the cardiovascular system, blood. The consequence of such violations gas exchange can be hypoxia, oxygen starvation of tissues. Cm. also the Gas analysis.