Blood in the human body performs many functions, it protects us, carries nutrients and oxygen to the tissues, and carries away carbon dioxide from them. Arterial is called blood, which contains oxygen, it is also called oxygenated. The addition of this gas, which is so necessary for the body, occurs to erythrocytes, which contain molecules of a specific protein, heme, which includes iron. Anatomists have long proven that arterial blood flows in the arteries, and then, giving up oxygen, it becomes venous and flows through the veins.
Arteries and their functions
Arteries are called vessels in which arterial blood flows. And they carry it only from the heart. The largest vessel of the human body, in which blood rich in oxygen flows, is the aorta; in an adult he althy person, its diameter is up to 2.5centimeters. Small arteries can be as small as 0.1 millimeters. Directly near the branch from the heart, the aorta is rich in elastic fibers, they soften the pulse wave that the heart gives, and the arterial blood then flows evenly through the vessels. Due to this, oxygen gradually passes into the tissues. Further, the walls of the vessels become less elastic and acquire more density, primarily due to the presence of muscle fibers. Arteries are connected with other arteries, this is called collaterals, due to them, when one vessel is blocked, blood can go in another direction. Each organ of the human body is constantly waiting for oxygen, which is so necessary in the processes of energy metabolism. The main function of the arteries is to deliver blood to them in the shortest possible time. There is a lot of oxygen in red blood cells, so the color of arterial blood is bright red, and when blood vessels are cut, it beats with a fountain, primarily due to the pressure that is in them.
Almost invisible but so necessary
The entire sacrament of oxygen transfer in tissues is carried out in capillaries, these are the thinnest vessels, where oxygen is exchanged for carbon dioxide. If everything is in order in the body, the capillaries are not visible, and in case of pathology, a capillary network may appear. The length of the capillary is no more than a millimeter, and its lumen is such that it passes only one erythrocyte. There are a huge number of such vessels in the body, they are called the capillary network.
What happens to oxygen in tissues?
In the body, oxygen takes part in the firstturn in the processes of mitochondrial oxidation. During this, the transformation of organic substances occurs, and, as a result, energy is formed, which is called ATP (adenosine triphosphate), it is this substance that is the universal and only energy source. Carbon dioxide, which was formed in the tissues during metabolism, enters the bloodstream, making it venous. Such blood flows through the veins, and when it enters the lungs, carbon dioxide is excreted from the body into the environment.
Arterial and venous
Definitely it is impossible to say that arterial blood flows in the arteries, and venous blood flows in the veins. Indeed, arterial blood is carried from the heart through the arteries. But this is only in relation to a large circle of blood circulation, but in a small one it is completely the opposite. Arterial blood flows in the pulmonary veins. Why exactly in the veins? Yes, it’s very simple, because veins are vessels that carry blood to the heart, but arteries are from it. Venous blood flows in the arteries of the lesser circle.
Gas composition
In order to understand how the lungs perform their functions, and how much oxygen the arterial blood contains, the gas composition is determined. The acid-base balance indicator will provide additional information that will reveal the secrets of kidney function or the presence of an infectious process in the body. An analysis of the gas composition will allow you to adequately and effectively select oxygen or oxygen therapy.
Before analysis
Before determining the gas composition of a person's blood, it is necessary to conduct an Allen test. It will allow you to understand what is the functional state of the circulatory system at the moment. Its essence is very simple and consists in the fact that the subject must clamp the ulnar or radial arteries located in the wrist area. They do this until the hand, or rather the palm, becomes pale. Next, it is worth releasing the vessels, blood circulation will be restored, and the palm should turn pink or red for no more than five seconds. Next, you can determine the gas composition, blood for this is taken from a vein. The degree of saturation of hemoglobin with oxygen depends on body temperature, acid-base balance, partial pressure of carbon dioxide. If the partial pressure falls below 60 mmHg, a decrease in oxygen saturation of red blood cells can be judged. After that, it is worth stopping the bleeding, for this, cotton wool is pressed tightly or a bandage is applied, which is removed no earlier than after 30–60 minutes.
