Structure and function of the heart. How does the human heart work?

The heart is the main organ of our body. It is on how it works, in what state it is, and the health of a person depends. And the functions of the heart - this is a very extensive topic, with which at least superficially everyone should be familiar.

Features of the structure

So, the first thing to note is that this organ is located on the left side of the chest. Although there is a small group of absolutely unique people in our world - their heart is on the right side. Usually such persons have a very peculiar structure of the organism, that is, a mirror structure. And, accordingly, the heart is also opposite to the usual location.

In general, this organ consists of four cavities - from the left and right atriums, as well as from the ventricles. These chambers are divided by partitions. The heart is quite peculiar in structure. The figure on which the organ is depicted clearly shows what it is. But the cavity is not the most important thing. Valves responsible for the flow of blood deserve special attention.

Location of the heart valves

The first thing to say about this part of the heart is that the pulmonary veins go to the left atrium, and the right ones go hollow. From the right and left ventricles emanates an ascending aorta, as well as a pulmonary trunk. So, this topic should be considered in more detail. The left ventricle is divided with the atrium (located on the same side) of the mitral valve, which is also called bivalve. And the right one is separated from the atrium by a three-leaf valve. Even in the heart, whose design allows for a detailed examination of the structure of this organ, there are aortic and pulmonary valves. They are responsible for the flow of blood from the notorious ventricles.

Circulatory process

What is the most important function of the heart? Naturally, blood circulation. Without this, the body could not function fully. Everyone knows that the heart carries two circles of blood circulation - small and large. The first of these starts in the right ventricle, and the end of it is in the left atrium. He is responsible for a full gas exchange in the alveoli of the lungs. Concerning the second it is worth noting that a large circle begins in the left ventricle, and ends, as you might guess, in the right atrium. He is responsible for providing blood, not only to the lungs, but also to other human organs. All this is fully realized only with a healthy heart.

Valve mechanism in operation

Much has been said about the valves and about what function the heart performs. Their work should be clear and well-coordinated. After all, the pumping function of the heart depends on the valves, which together form a whole mechanism. The tricuspid opens and the blood passes into the right ventricle from the atrium. As soon as it is filled with blood, the valve under the influence of muscle pressure closes. And then the blood can exit only through the pulmonary trunk, into which the pulmonary valve opens, opening under the pressure of blood, which increases during contraction of the right ventricle. And blood can enter there only if the mitral valve is open . The entrance to the aorta is closed by the aortic valve, which consists of three valves, which resemble the appearance of the crescents. When the left ventricle is relaxed - it is closed, and so the venous blood passes into the right atrium. Thus, blood circulation is carried out. Of course, in words it's all very long, but in reality it takes only a moment. Our heart works so quickly.

Facts to know

The structure and functions of this body are not only important, they are also interesting. For example, not everyone knows that blood circulation is carried out about 100,000 times a day at a distance of about 100,000 kilometers! It is amazing, but this is the length of all the vessels of our body. And if we talk about how many times a year our heart is reduced, then the figures are simply astronomical - more than 34 million! And, finally, the latest data - for this time interval the heart pumps three million liters of blood. This is incredibly much. So, if you ask yourself about the function of the heart, you can definitely say it is vital. And it does a great job for this. It is worth noting one more nuance: for one single reduction, the amount of energy that is enough to raise the weight of 400 grams of weight to a height of 1 meter. And this is in view of the fact that the heart, being in a calm state, spends only 15 percent of the quantity of its reserves that it has. But if the body performs hard work, then it spends 35% of its energy. This is our heart, the structure and functions of which are really special and unique.

Myocardium and its specificity

Here you can talk for a long time and quite a lot. Take, for example, contractile cells of the myocardium. Discussing the functions of the heart, it is impossible not to mention this point. The fact is that they have worked without stop for many years. Therefore it is very important that they are constantly supplied with air. The lack of oxygen and other nutrients adversely affects the function of the human heart. If they do not act, the cells will begin to die, and instantly. After all, they do not make stocks that could be useful in such cases. The life of the heart cells is a relentless blood circulation. And the muscle, which is full of blood, can starve. After all, the myocardium does not feed on the blood that fills its cavity. Oxygen and all nutrients go through the vessels that leave the aorta.

Pumping function

Is one of the main. And it consists in alternating diastole and systole of the heart ventricles - this is alternating their relaxation and contraction. When the diastole is carried out, the ventricles are filled with blood. If a systole occurs, they transmit blood to the pulmonary trunk and into the aorta, that is, into the large arteries. As you can remember - next to the ventricles are heart valves, which are an obstacle to the return flow of blood into the heart of the artery. After all, blood, before filling the ventricles, passes through the large veins straight to the atrium. Abbreviations are the precursor of ventricular systole. We can say that the atrium is a kind of auxiliary pump that helps fill the ventricles.

Functional elements of the heart

Their importance is just as important as the work done by the valves. Muscle fiber is just one of the functional components. This is a chain composed of myocardial cells, which are connected to one another and are enclosed in a single sarcoplasmic membrane. It should be noted that the fibers are divided into several types. Everything depends on their functional, as well as morphological, individual characteristics. The first type is the fibers of the myocardium of the ventricles and atria. They make up the main muscle mass and are the ones that provide the injection function. And the second type is the muscle fibers of the so-called conducting system. They are responsible for the appearance of excitation, as well as for its transmission to the cells of the myocardium. So the increasing heart rate is a consequence of a violation in the functional components of the human body.

Consequences of cardiac dysfunction

On how well the functions of a person's heart function, his health depends, as already mentioned. Unfortunately, today many suffer from diseases associated with this body. They are actively sick people elderly and old. And this is due to what was mentioned - this body works without stopping throughout life, and it is not surprising that after 50-60 years of continuous labor, it gets tired. Three out of five people die because of heart disease, mainly from heart attacks.

Diseases include three main groups of ailments that affect the vessels, valves and tissues of the membranes. For example, atherosclerosis is a disease that affects the heart vessels. By the way, the most common ailment. Or heart failure, too many suffer it. Even serious illnesses must be attributed vice. The essence of the disease lies in the violation of any function of the heart valves. And vice can be either acquired or congenital. Arrhythmia also occurs if the functions of the human heart are violated. Most often, it appears due to the downed sequence, frequency or rhythm of the heartbeat. Some people suffer from angina (oxygen starvation). And finally, attention should be noted such a violation as myocardial infarction. A variety of ischemic disease - when this disease occurs, the site of the myocardium ceases to be saturated with blood, or it does not happen as intensively as usual.

Cardiopalmus

Proceeding from all of the above, it can be understood that if some changes occur with our main organ - then this is definitely a violation of any function of the heart. Perhaps the most common and most commonly observed ailment is rapid heartbeat. This may be a tachycardia that occurs due to ischemic disease, myocarditis, myocardial dystrophy, or due to a defect. But sometimes this ailment is not connected with the heart - it can be because of a thyroid gland, menopause or a tumor that has developed itself. Many people simply do not pay attention to periodically arising pains or strange sensations. And in vain, because our heart is under tremendous strain. Particular attention should be paid to this in the event that your own activity is associated with nervous work, stress and disruption.

Additional functions

In addition to the circulation of blood, this important organ has other possibilities. What are the main functions of the heart should be highlighted yet? Perhaps, so-called automatism is its ability to produce such impulses that provoke stimulation. The biggest automatism is the sinus node. One can not forget about the conductivity - the function of the myocardium, or rather its ability to transmit impulses straight to the contractile part of the heart. Actually, excitability is the process of increasing heart rate under the influence of impulses. And, of course, the refractoriness, consisting in the absence of the possibility to activate the excited cells of the myocardium in the event that additional signals began to flow to them. It divides into absolute (when the heart is absolutely apathetic in relation to any stimulation), and also on the relative (the organ reacts to a very strong manifestation). So the functions of the human heart are endless.

The only thing I would like to note is that it is necessary to take care of it. After all, this organ is very important, and it is from his condition that the duration of a person's life depends. Thus, proceeding from the foregoing, it can be stated with certainty that the heart, structure and functions of which have been examined in detail, is a mechanism consisting of a mass of vessels, cavities and valves linked together by one goal - to provide a full blood circulation. After all, it is necessary for the life of any living being. So this is exactly what the basic functions of the heart are.