If you put your hand on your wrist, you will immediately feel rhythmic jolts. It works your heart by pumping blood.

Let's see what it is for?

Everyone internal organs your body needs food and oxygen. All this is delivered to them by blood flow - a special fluid that fills numerous blood vessels. But the blood must move, pass through the whole body. This is what the heart does, acting like a normal pump.

The heart consists of several closed cavities with thick, muscular walls. The main work is performed by the ventricles of the heart. Their muscular walls contract and force the blood to move. The most powerful left ventricle, thanks to which blood circulates throughout the body.

First, the blood passes through the largest artery - the aorta. Then this main vessel is divided into smaller ones, heading to all the internal organs. Branching, the vessels diverge throughout the body to ensure the delivery of nutrients and oxygen.

Passing through the body, the blood is saturated with the waste products of cells. Vessels through which the reverse movement of blood occurs are called veins. Through them, the blood is sent to the kidneys, where all substances harmful to the body are removed from it.

After that, the blood again reaches the right half of the heart and is sent to the lungs, where it is saturated with oxygen. Then it enters the left half of the heart, and the whole cycle begins again. This process is called circulation.

Video: how the heart works

Let's start with what, what is love from the point of view of science.

The most vivid impressions and emotions come to people when they love, madly in love. And in this state of being in love, a substance with interesting name phenylethylamine, it is also called the "substance of love". At this moment, it seems that you have grown wings, that you are ready for absolutely any feat. And this happens because this love drug affects the logical centers of consciousness, so all subsequent actions of such a person cannot be rationally explained. Probably everyone who has ever experienced love has a story about such reckless acts that he did during his love ... Scientists studying the mechanisms of depression and elation have recently made significant discoveries regarding chemical compounds in the human brain, called neurotransmitters. The progenitor of all neurotransmitters, the one that makes men and women go crazy, can be considered a substance called phenylethylamine, or simply PEA. The mechanism of action of FEA is as follows: human brain is divided into separate sections, and in general it resembles a large grapefruit in size (although when a person loses his head because of love, we can safely say that his brain shrinks to the size of a pea). The first of the sections is located exactly above the spinal cord and is responsible for such instincts as the instinct for survival, the instinct for protecting the territory, etc., these are the most important instincts of human life. The next area, the limbic system, governs such emotions as anger, depression, hatred and their opposites: calmness, contentment, love. The third region, the cortex, is most similar to a ball of pasta and is what we think of when we think of the brain. This area is responsible for our thought processes. All these three areas are interconnected by hundreds of billions of nerve impulses (the difference varies by plus or minus a couple of billion, depending on the individual), which are transmitted from neuron to neuron. FEA is on the endings nerve cells and helps impulses move from one neuron to another. But there is one problem: PEA itself is a natural amphetamine that takes us to seventh heaven. Therefore, when you see a person to whom you are ready to surrender without a fight, the system that produces FEA immediately begins to overfulfill the plan. PEA flows overwhelm all parts of the brain - including the one that is responsible for rational thinking. Therefore, you not only endure the intrusion of a loved one on your own territory, but also feel (through the efforts of the limbic system) incredibly happy (or terribly unhappy, depending on the circumstances). The fact is that when a person sees the person he fell in love with, then adrenaline is produced in him, and the heart begins to shrink, I think that's why people think that they fall in love with their hearts

The heart is the most hardworking organ, the work of which does not stop throughout life. This is a powerful motor of the body, which supplies other organs and muscles with oxygen and useful substances through the blood and lymph. Despite its importance, the heart is a relatively small organ, it is believed that it is commensurate with the size of the fist of its owner. This organ has the shape of a cone slightly flattened vertically. The weight of the heart can reach 300 g of a person, and the baby weighs only 20-25 g and resembles a large strawberry in shape. The work of the heart is a complex cyclic contraction process, the stages of which last no more than a second. For example, at rest, it contracts 60-70 times per minute, with physical activity or the heart rate may go up to 160 beats per minute. The heart has a very complex structure, but it can be divided into two parts: the left and right chambers, which work in isolation from each other. The chambers, in turn, are divided into the atrium and ventricle. The work of the heart is controlled by the nerve node located in the right, it is responsible for the contractions of the organ and their frequency. The node sends signals to different parts of the heart, making them work. Blood from the body flows through the veins to the right chamber. This blood is oxygen depleted because it has already carried it to its intended destination, so the heart sends it to the lungs. The blood is enriched with oxygen and returned to the left chamber, which, in turn, sends it further. Thus, the blood supply to the tissues of the body is the main task of the heart, which acts as a natural pump. For a full human life (about 70 years), the heart makes about 2.5 million contractions. The contraction of the heart muscle consists of two stages: systole and diastole. These complex terms actually mean action and pause. Systole - filling with blood from the body of the right atrium and sending it to the lungs. The production of oxygen-rich blood occurs during diastole (pause), when blood drains from the lungs into the left atrium for further distribution to body tissues. Diastole is a period of rest, which lasts about 0.4 seconds. Due to the presence of its own nerve node, the heart works in isolation from other organs of the body, the action of which is controlled by the brain. Nature provided for the protection of the heart from possible external influences, placing it in the depths of the chest and covering it with ribs and lungs. In addition, the heart has a protective shell, a kind of sheath, which is called the pericardium and consists of connective tissue.

Related videos

The heart is one of the main organs in the human body. All life it is in motion, distilling blood through the body. This is facilitated by the complex structure of the heart.

chambers of the heart

The heart is a hollow muscular organ in the shape of a cone. It is surrounded by a pericardial sac, which performs a protective function and reduces friction during contraction. The heart is divided into 2 halves by a septum. Each of the halves is further divided into an atrium and a ventricle. The atria are located at the base, which faces upwards and backwards. The ventricles are located at the apex of the heart, this is its lower end.

The atrium and ventricle are connected by openings, these openings have valves. In the right half of the heart, the valves consist of three valves, in the left - of two. These valves open only in one direction, towards the ventricle. The opening to the other side is prevented by tendon threads attached to the edges of the valves. At the other end, these threads are attached to the papillary muscles on the inner surface of the ventricles.

Veins approach the atria: to the right - the upper and lower hollow, to the left - four pulmonary veins. The vessels depart from the ventricles: - the pulmonary trunk, from the left - the left aortic arch. This aorta also has two coronary arteries that supply blood to the heart. Where the formations of the circulatory system depart from the ventricles, there are semilunar valves. These valves are like pockets, they release blood from the ventricles. Reverse current is not produced.

The structure of the heart wall

The wall of the heart includes three layers: epicardium, myocardium and endocardium. The predominant part is the myocardium. The epicardium is outside, it is a connective type of tissue. In addition to the heart itself, the epicardium covers the initial sections of the pulmonary trunk and aorta, the final sections of the pulmonary and vena cava. The endocardium is the inner layer of the heart wall, it consists of a single layer of cells. The heart valves are essentially folds of the endocardium.

The middle layer is the myocardium, it is a striated muscle tissue. In the left ventricle, this layer is best developed, because it accounts for the largest amount of work. Its walls are 2-3 times thicker than the walls of the right ventricle. The myocardium of the atria and ventricles is separated from each other by fibrous rings so that they can contract separately from each other.

During the work of the heart, periods of relaxation are combined -, and periods of contraction - systole. First, blood flows from the atria to the ventricles. After the ventricles begin to contract, and blood enters the pulmonary trunk and aorta. The atrioventricular valves then close and the semilunar valves prevent blood from returning.