How is the heart of man, what are its functions?

The heart in the human body is a vital organ. His work can be compared to a pump. Thanks to the heart, blood is injected into the arteries and continuously moves along the vessels. The body functions throughout the life of a person. Over 70 years, it roughly performs 2-3 billion cuts and pumps more than 170 million liters of blood. So, how is the heart arranged? What are its functions?

Location and size of the heart

The main organ of the human body is in the center of the chest. The greater part of the heart is located in the left half of the body, and the smaller part in the right half. The organ lies in the pericardial bag. It is also called the pericardium. This is a tight bag that fences the heart from other internal organs and does not allow it to shift and overstretch at the time of physical exertion.

The size of the heart is rather small. Every person has about a fist. However, the size and weight of the organ can vary. The parameters increase with some ailments. The size and mass of the heart also increases in those individuals who for a long period of time engage in sports or hard physical labor.

Structure of the organ

Let's see how the heart works. The walls of this organ form three layers:

1. Epicardium. This is a thin membrane outer layer of the heart wall.
2. Myocardium. By this term, specialists understand the middle layer responsible for muscle contraction of the heart.
3. Endocardium. It is a membrane that limits the internal system of the heart.

This vital organ consists of two parts, separated by a septum - a thick muscular wall. Each half includes two cameras. The upper divisions (right and left) are called atria, and the lower ones are called ventricles. Each chamber plays a special role in the process of circulation.

Atria

Considering how the heart is arranged, it is necessary to talk about atriums - thin-walled chambers of the heart. They are located above the ventricles and are separated from them by atrioventricular valves. Allocate the right and left auricles. The right upper organ chamber is the place of the confluence of the hollow veins and veins of the heart itself. Based on this information, it can be concluded that this atrium receives venous blood deprived of oxygen.

The left upper organ chamber is smaller in size than the right one. It opens four openings of the pulmonary veins. Of these, fresh blood is supplied to the left atrium, saturated with oxygen and ready for further distribution throughout the human body.

Ventricles

On the picture, which shows how the human heart is arranged (photo below), you can see the right and left ventricles. They form the basic muscle mass of the organ. It is worth noting that the left camera compared with the right is more massive and powerful. The right ventricle receives venous blood from the right atrium. With a contraction of the heart muscle, it is sent to the lungs through the pulmonary valve. The back flow of blood in the upper chamber is hampered by the tricuspid valve, also called tricuspid.

The left ventricle receives blood from the left atrium saturated with oxygen. It comes through a mitral (two-leaf) valve. When the muscles of the left lower chamber contract, the blood is pushed into the aorta through the aortic valve. Then it spreads all over the human body.

Heart Work

When considering how the heart is arranged, it is necessary to study the work of the organ. Ventricles and atria may be either in a relaxed (diastolic) or in a contracted (systolic) state. Relaxation and contraction of the heart occur in a certain sequence:

1. Atrial systole. Reduction of the upper chambers of the organ is the beginning of the cardiac cycle. This phase lasts 0.1 s. During systole, the valvular valves open. All the blood from the atria is sent to the ventricles. After the reduction of the upper chambers, the relaxation phase begins.
2. Ventricular systole. Reduction of the lower parts of the heart lasts 0.3 seconds. Semilunar (pulmonary and aortic) and valvular valves at the beginning of the phase are closed. The muscles of the ventricles contract. Because of this, the pressure in the cavities rises. As a result, the blood is sent to the atria. There the pressure is lower. However, the blood flow in this direction is hampered by the flap valves. Their valves can not turn inside the auricles. At this point, the semilunar valves are opened. Blood begins to move along the pulmonary artery and the aorta.
3. Diastole. The ventricles relax after relaxation. This phase lasts 0.4 s. During the rest period of the organ, blood flows from the veins into the atria and penetrates partially into the ventricles. When a new cycle begins, the remaining blood from the upper organ chambers is pushed out into its lower parts.

Considering how the heart is arranged and how it works, it is worthwhile to talk about the circulatory circles - large and small. The first of them begins with aorta. Into it from the left ventricle comes enriched with oxygen blood. From the largest arterial vessel, it flows through arteries, arterioles, capillaries, delivering oxygen to all cells and freeing them of accumulated carbon dioxide. As a result, the capillary network leaves venous blood. First, it moves along the veins, and then - through the veins and hollow veins. As a result, she falls into the right atrium, and from it goes to the right ventricle.

The small circle of blood circulation begins with the pulmonary artery leaving the right lower chamber of the heart. Venous blood enters the lungs, moves along arteries, arterioles and the thinnest capillaries located in these organs. As a result, it gets to the alveoli - tiny vesicles, which are filled with air. Blood absorbs oxygen, is purified of carbon dioxide and enters the veins. These blood vessels go to the left atrium. From it, the blood is pushed into the left ventricle. Then everything repeats itself again. Blood begins to move along a large circle of blood circulation.

Functions of the body

Having considered how the heart is arranged, its functions can be called. One of them is a reservoir tank. The vital organ of the human body during the relaxation of the heart muscle serves as a cavity for the accumulation of a regular portion of blood coming from the blood vessels to the atria. The second function of the heart is injection. It consists in the ejection of blood into the small and large circles of the circulation when the ventricles contract.

How the heart of man is arranged, everyone should know. Everyone needs to have information about how his body is arranged, what processes are taking place in him. The health of a person depends on the work of the heart. Thanks to the functioning of this organ, the blood spreads throughout the body, supplies all organs and tissues with oxygen, biologically active substances, energy, and takes away carbon dioxide and separation products.