Blood in the human body performs many functions, it protects us, transfers nutrients and oxygen to tissues, and carbon dioxide carries away from them. Arterial is called blood, which contains oxygen, also it is called oxygenated. The addition of this gas, so necessary to the body, occurs to red blood cells, which contain in their composition molecules of a specific protein, heme, which includes iron. Anatomists have long proven that arterial blood flows in the arteries, and then, giving 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 oxygen-rich blood flows, is the aorta; in a healthy adult, its diameter is up to 2.5 centimeters. Small arteries can reach as little 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 further flows uniformly through the vessels. Due to this, oxygen gradually passes into the tissues. Further, the walls of the vessels become less elastic and gain more density, primarily due to the presence of muscle fibers. Arteries are connected with other arteries, this is called collateral, due to them, when one vessel becomes clogged, blood can go through another. 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. Red blood cells have a lot of oxygen, so the color of arterial blood is bright red, and when the vessels are cut, it beats with a fountain, primarily due to the pressure that is in them.
Almost invisible, but so necessary
The whole mystery of the transition of oxygen into tissues is carried out in the 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 with pathology, a capillary network may appear. The capillary is no more than a millimeter long, and its lumen is such that it passes only one red blood cell. The body has a huge number of such vessels, they are called the capillary network.
What happens to oxygen in tissues?
In the body, oxygen takes part primarily in the processes of mitochondrial oxidation. During this, the transformation of organic substances occurs, and, as a result, energy is generated, which is called ATP (adenosine triphosphate), it is this substance that is the universal and only energy source. Carbon dioxide, which in the process of metabolism was formed in the tissues, entering the blood, makes it venous. Such blood flows through the veins, and getting into the lungs, carbon dioxide is removed from the body into the environment.
Arterial and venous
It cannot be stated unequivocally that arterial blood flows in arteries, and venous blood flows in veins. Indeed, arterial blood is carried through the arteries from the heart. But this is only in relation to the large
circle of blood circulation, but in the small one the opposite is true. Arterial blood flows in the pulmonary veins. Why in the veins? Yes, it’s very simple, because veins are vessels that carry blood to the heart, but arteries from it. Venous blood flows in the arteries of the small circle.
Gas composition
In order to understand how the lungs perform their functions, and how much oxygen contains arterial blood, a gas composition is determined. The acid-base balance index will provide additional information that will reveal the secrets of kidney function or the presence of an infection 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 human
blood , it is necessary to conduct an Allen test. It will help 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 it is necessary for the subject to clamp the ulnar or radial arteries located in the wrist. Do this until the hand, or rather the palm, becomes pale. Then it’s worth letting the blood vessels go, blood circulation will restore, 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 drops below 60 millimeters of mercury, a decrease in oxygen saturation of red blood cells can be judged. After that, it is worthwhile to
stop the bleeding, for this purpose they firmly press cotton or apply a bandage, which is removed no earlier than after 30-60 minutes.