How the human heart is arranged

How the human heart is organized for more than three centuries. But it has not been fully understood until now. It remains a mystery what or who gives the first push to the heart. At first, it was assumed that the signal to the first life-beating comes through the cardiac nerves or myocardium. Then they found out that the heart of the fetus makes the first push before the nerve endings grow into it. The ear of the heart begins to contract already in the third week after conception.

Heart.

As a result of experiments on animals, it became clear that if you cut the nerves that connect the heart to the spinal cord and brain, cardiac activity will not stop. It is known that the heart beats for a while even after full extraction from the body. Moreover, the heart is arranged so that if you cut out a piece of the heart muscle and put it in physiological saline, it will shrink at the rhythm in which the heart has previously contracted.

The human heart has a mechanism of self-management, which is in the form of nodules in a cluster of nerve cells. Bioelectric impulses in the heart muscle arise automatically. They make the heart rhythmically contract. The fibers of the intracardiac nervous system innervate not only the heart muscle, but also the musculature of the coronary vessels. Scientists still do not understand how these "nervous" devices function.

The heart is a miniature power station that generates electricity. The electric field of the human heart reaches its maximum at the moment of contraction, with physical and emotional stress. The electric field of the heart in space spreads with light speed. Perhaps, this explains that close people at a great distance feel that something has happened to the beloved person.

Technically, the heart is a pump that pumps blood. And the blood, in turn, delivers to every cell of the body food and oxygen, and on the way back absorbs waste life and carbon dioxide. Without a heart and blood vessels of different diameters, life would not have developed into complex forms and would have frozen at the level of simple organisms. In humans, only veins, capillaries and arteries have a total length of about 100 thousand kilometers!

Circulatory system.

The onset of the circulatory system is the aorta. It departs from the heart, dividing into arteries, arterioles and smallest capillaries. From the beginning of the aorta, coronary arteries branch off, each about 10 cm in length. They envelop the heart, providing it with oxygen and nutrients. Inside the vessels are muscles that narrow and widen the passage. Each vascular has its own nervous regulation, which is subject to capillaries from the center.

Compressing, the heart drives blood through the arteries. And relaxing, loads the veins, through which the used blood is extracted from the tissues of the body. The heart needs a lot of oxygen. Having an average mass of 310 g( half a percent of body weight), it consumes up to 70% oxygen. That is, the rest of the body remains only 30%.

The human heart is designed so that the more it contracts, the greater the pressure in the arterial system. Arterial pressure is always greater than the venous pressure, because a powerful flow of blood after the contraction of the heart collapses on the arteries. The normal pressure at the time of contraction of the heart( arterial) is 120 mm Hg. And at the time of relaxation of the heart( pressure in the veins) - 70/80 mm.

The heart of a person pumps 5-8 liters of blood in one minute. For a day the volume reaches 7500 liters. And for human life( 70 years) - about 400 thousand tons. The heart is able to reduce for a day 100 thousand times.

The heart shrinks rapidly, for each cycle it takes only 0.7-0.8 seconds. And the contraction of the ventricles lasts 0.3 seconds, and the remaining time the heart relaxes. For 0.4-0.5 seconds of relaxation, it can fill with a new portion of blood. If the heart does not work for more than five minutes, life stops.

On the device, the human heart seems simple. In fact, this is an amazingly perfect system, melting puzzles for modern science. It works without rest all our lives. Therefore, he needs to help, no matter how banal, healthy way of life.