Alveolus

Alveolus (from Lat. Alveolus - the cell cavity, a bubble) - puzyrkovidnoe formation in the lung, braided network of capillaries.

The walls of the alveoli are very thin: they consist of only one brand name viagra cell layer. Capillary walls also consist of a single layer of cells. Consequently, being in the alveoli and the air flowing through the blood capillaries are separated by only two layers of cells. Here through the thin wall and gas exchange occurs. The nature of the gas exchange that occurs in the lungs, can be judged by comparing the composition of inhaled and exhaled air.

We breathe the air. It contains 20.94% oxygen, 79.03% azotairaznyh inert gases (argon, neon, helium, etc.) and 0,03% carbon dioxide. The composition of the exhaled air is different: the oxygen in it 16,3%, 4% carbon dioxide, nitrogen and other inert gases, 79.7%.

Contrast these figures. You can see that the amount of oxygen in the lungs decreases, and carbon dioxide - is increasing. Oxygen from the air in the alveoli, goes to the blood and carbon dioxide leaves the blood and passes into the alveolar vozduh.Krov, entering through the pulmonary artery to the lungs, spreads in the capillaries of the huge area of a thin layer of alveoli. It also contributes to gas exchange.

Oxygen, passing from alveolar air into the blood, enters into a chemical bond with hemoglobin.

Oxygenated blood is carried throughout the body and in capillaries of tissues giving oxygen. Here in the blood to carbon dioxide. Oxygen, which gives the blood to tissues is the cell and enters into the chemical processes of metabolism.

In a chemical bond with the hemoglobin is not only oxygen but also other gases. Chemical bonding of hemoglobin with oxygen is very unstable. It is easily formed and easily broken. Exceptionally strong association of hemoglobin with carbon monoxide - carbon monoxide. This strength and Caution against nitrates due to toxic effects of carbon monoxide. Carbon monoxide is so firmly connected with hemoglobin, the oxygen can not enter into relationship with him and did not come to the cells and tissues - a person die from suffocation if you do not make the victim to fresh air.

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