Circulatory system in the human bodyallow the blood to perform all the necessary functions. The essence of the blood circulation is the movement of blood through the vessels to provide the necessary substances to all human organs. The whole system of the circulatory system is composed of blood vessels and heart. Due to the contraction of the heart muscle, the blood is carried through the vessels. There are two types of vessels: arteries (carry blood from the heart muscle to organs and tissues) and veins, through which blood flows to the heart. Between themselves all the vessels are connected by the smallest blood capillaries.
A person is distinguished by the following circlesblood circulation: small, large. The trunk or large circle originates in the left ventricle of the heart. Then the blood flows into the main artery in the human body - the aorta. From the aorta, the blood spreads along the spine, thanks to the smaller arteries. Having reached the organs, arteries are divided into arterioles, smaller vessels, which in turn are divided into capillaries. So the organs and tissues are saturated with oxygen and nutrients necessary for the normal functioning of the body. Similarly, starting from the capillaries, the venous blood enters two large veins of the body, the lower and upper. Then it is delivered to the right atrium. The whole cycle is the big circle of blood circulation.
Pulmonary, or otherwise a small circle,blood circulation does a shorter path. From the right ventricle of the heart leaves a large artery, which is divided into two pulmonary arteries. So the blood enriched with oxygen is delivered to the lungs. Large arteries are divided into arterioles, and those, in turn, are divided into capillaries. It is they that make it possible to saturate the lungs with oxygen and to purify it of carbon dioxide. This is the exchange of gases in the lungs. Then the venous blood flows through the veins into the left atrium.
Small and large circles of blood circulation are similarfunctions of all organs. Arteries deliver blood, saturated with nutrients and oxygen, to organs and tissues. The veins, in turn, return the venous blood to the heart. The only difference is the distance: large and small. Circles of blood circulation perform the function of saturation of body cells with oxygen.
But the circles of blood circulation do not transfer all the blood,which is in the body. Some blood is retained in the blood depots. They are in the spleen, liver, lungs and in the accumulation of blood vessels under the skin. Such depots are necessary for emergency saturation of organs and tissues with oxygen.
Blood distribution between individual organsthe body is not evenly distributed. Blood circulation circles supply blood depending on the activity of the organ or tissue. This occurs as the vessels expand and contract. Blood to the actively working body comes in a larger amount due to lower blood flow in other, less active organs.
Circles of circulation work at the expense of the systemblood vessels, and of course, the heart muscle. Arteries respond to the delivery to organs and tissues of blood enriched with oxygen and nutritional components. Thanks to them, high blood pressure is maintained, ensuring rapid blood circulation through the capillaries and saturation of tissues and organs.
The blood that has passed through the circulation circles contains the products of the vital activity of the human body and carbon dioxide. Such blood carries vessels, which are called veins.
Capillaries also play an important role in the wholecirculatory system. This is a branched network of small vessels, through which the blood, saturated with nutrients and oxygen, flows directly into the muscles and tissues of the organs.
The whole circulatory system is of great importance in the life of the body. The heart, blood vessels and circulation are its main components.
