Small Circle Circulation

In humans, circulation is closed. Closed it because it does not have a message with the external environment. In addition, the blood circulation of a person is complete and double. Full it is called because the blood (venous and arterial) is not mixed.

In the body, a large and small circle of blood is isolated. There is also a third. It is also called "heartfelt" and performs quite important tasks.

The pulmonary (small) circle of blood circulation begins in the right ventricle. The main function is to saturate the blood with oxygen, in eliminating carbon dioxide. In the lungs, gas is exchanged.

The small circle of blood circulation is represented as follows. Poor blood oxygen (venous) comes from the ventricle (right) into the pulmonary trunk. The trunk (the largest artery that is included in the small circle of the circulation) is divided into the left and right arteries (pulmonary). From the right, the admission goes to the right lung, from the left - to the left, respectively. Then there is a multiple separation of the pulmonary arteries into smaller ones.

The small circle of blood circulation includes capillaries, which very closely approach the inner surface of the lungs. This surface is in contact with the air of the atmosphere. The blood in the capillaries is separated from the air only by the walls of the capillaries themselves and by a very thin wall of the lungs. These barriers are so thin that in normal conditions carbon dioxide and oxygen are able to penetrate without difficulty through them. Thus, they move from areas of higher concentration to areas of lower concentration. In connection with the fact that in the veins of carbon dioxide more, it passes into the air, where it, respectively, less. And, since there is more oxygen in the air, it passes into the capillaries.

Some pulmonary capillaries join and flow into large vessels. Those, in turn, penetrate into even larger vessels - into the veins. As a result, four large veins (pulmonary) are formed. Thus, the small circle of blood circulation ends in the left atrium.

The cycle time at rest is on the order of four to five seconds. A small circle of blood circulation involves the movement of venous blood through the arteries, and the arterial blood flow through the veins.

There is time for a complete circuit. During this time, the blood passes both circles - both small and large. In rest it takes about twenty to thirty seconds. Muscle tension contributes to increased speed. As a result, the passage of blood on both laps can be from eight to nine seconds.

Speaking about the movement of red fluid in the body, it is necessary to mention the organs that participate in it. So, in the circulation, ventricles and atria, arteries, aorta, capillaries, lower and upper hollow veins, pulmonary capillaries and arteries, veins, alveoli, and the coronary artery are involved.

With the help of blood vessels there is a movement of blood between different organs, tissues and heart. Arteries come out of the heart. They send blood to tissues and organs. Arteries are distinguished by a large diameter and thick elastic walls, which can withstand a sufficiently high blood pressure.

Arteries consist of several shells: inner, outer and middle.

The lumen of the vessels is regulated by the nervous system (vegetative) and can decrease or increase due to the work of smooth muscles. The increase or decrease will depend on the needs of one or another body, as well as the temperature of the environment.

Arteries in tissues and organs pass into vessels with a smaller lumen, eventually becoming capillaries. They exchange nutrients and other elements necessary for life between cells and blood. Capillaries, in turn, connect the venules and arterioles.