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Why is the heart able to work continuously. Heart failure

Kirikov Tatyana Alexandrovna

Lesson Objectives:

educational:

introduce the structure of the heart; reveal the relationship between the structure of the heart and its functions;
give concepts: cardiac cycle, automatism of the heart, conduction system of the heart;
realize the possibilities of hygienic education.

developing:

activate cognitive activity students by solving problematic issues;
continue to form information competence, the ability to draw conclusions.

educational:

education of kindness, sensitive, mutual respect for others.

Planned results:

name the structural components of the heart, name the phases cardiac cycle, define concepts on the topic, describe the mechanism of the course of the cardiac cycle, explain the phenomenon of automation, high performance of the heart, name the types of blood circulation regulation, describe the mechanisms of nervous and humoral regulation of blood circulation, the effect of alcohol, tobacco on the cardiovascular system; explain: justify the need for a healthy lifestyle; work with various sources of information.

Lesson type: a lesson in the assimilation of new knowledge by the method of problematic presentation of new material

Plan for studying new material:

Determination of the size and position of the heart in chest cavity.

The structure of the heart.

Automatic heart.

Cardiac cycle.

Regulation of the heart.

Influence of environmental factors on the heart.

Problem questions:

Why does blood only move in one direction?

Why can the heart contract throughout life without noticeable fatigue? When does it rest?

Why does the heart “behave” differently? What is happening to him?

New terms and concepts:

pericardial sac, flap valves, semilunar valves, automatism, cardiac cycle, phases of the cardiac cycle; atrial, ventricular contraction, pause, sympathetic and vagus nerves, adrenaline.

During the classes

I. Organizing time.

II. knowledge motivation.

Every person always, all his life thinks about love, needs it, waits for it, strives for it!

Strange, we talk about love in biology class.

Maybe biology is somehow connected with the symbol of love?

What is portrayed when someone is loved? (slide 1)

Today in the lesson we will try to answer the question, why the heart?

And not the eyes, not the ears, not the stomach are a symbol of love?

Guys, what do you know about our heart?

How do you calculate what we should study in our lesson?

The topic of today's lesson is called "The structure and work of the heart"

Purpose: to study the structure and work of the heart.

III. Learning new material

1.-Does the heart look like this symbol depicts?

Let's get acquainted with the structure of the heart. Let's start with its location. (Slide 2)

The word "heart" comes from the word "middle". The heart is between the right and left lungs and only slightly shifted to the left. The apex of the heart is directed downward, forward and slightly to the left, so the heart beats are most felt to the left of the sternum.

The size of a human heart is approximately equal to the size of his fist.

Imagine its dimensions.

2. The heart is a hollow muscular organ, shaped like a cone. The muscular wall of the heart consists of three layers:

epicardium – the outer layer is made up of connective tissue.

Endocardium - the inner layer is formed by epithelial cells.

Myocardium – middle layer. This is the heart muscle, formed by the striated muscle tissue, which has the ability to contract regardless of the will of the person.

Slide 3.

The heart is located in a connective tissue sac called the pericardial sac. It does not fit snugly to the heart and does not interfere with its work. Besides inner walls pericardial sac secrete a fluid that reduces friction against the walls of the heart sac. (Slide 4).

Remember what departments the mammalian heart consists of?

There are 4 chambers in the heart: 2 atria and 2 ventricles. Between the left and right parts there is a septum that prevents the mixing of blood.

Arises problematic issue: If blood cannot move through the septum, then how does blood move through the heart?

I propose to work with the textbook p. 80, 2, 3 paragraphs, fig. 41, a route sheet that everyone has on their desks.

Exercise 1. Answer the questions.

1. What departments does the right and left parts of the heart consist of?

2. What valves are between them? Let's fill in the 1st part of the scheme "Heart valves" in the route sheet.

3.What are valves for?

4. Where does blood come from the ventricles and what valves are there?

Run time (5min)

From your answers, you can conclusion.

Blood moves in one direction: from the atria to the ventricles, from the ventricles to the arteries.

Let's write output 1 to the route sheet.

Consider the structure of the heart again using the model of the heart. Note that the walls of the left ventricle are thicker than the walls of the right ventricle, because the left ventricle does a lot of work - it pushes blood around the systemic circulation. The largest artery, the aorta, departs from it, the pulmonary artery from the right ventricle, and blood enters the heart through the veins.

Look carefully, is the thickness of the walls of the heart the same?

(No, the walls of the atria are thinner than the walls of the ventricles.)

What do you think it depends on?

(This is due to the fact that the atria make a little work. When they contract, blood enters only the ventricles, and the ventricles push the blood along the entire length of the blood vessels, i.e. do a great job).

Why are the walls of the left ventricle thicker than the right?

(The left ventricle does a lot of work, it pushes blood through the vessels of the systemic circulation).

Yes, indeed, the thickness of the muscular walls of the heart depends on the load.

Exercise. Let's work with the itinerary.

Do the exercise "The structure of the heart" (4 min)

So, we examined the structure of the heart.

What do you think is the main function of the heart? (Ensuring a continuous flow of blood through the vessels).

3.Let's watch a video about the work of the heart.

The heart is an amazing and reliable organ - a pump that works tirelessly throughout life, without stopping and repair.

Scientists have calculated that the heart pumps 10,000 liters of blood per day and spends on it such an amount of energy that would be enough to lift a load weighing 900 kg to a height of 14 meters.

But the heart works continuously for 70-80 years or more! The blood pumped by the heart during a person's life can fill 4375 railway tanks. And if the heart pumped not blood, but water, then from the water it pumped over in 70 years it would be possible to create a lake 2.5 m deep, 7 km wide and 10 km long. You see that the work of the heart is very significant.

You saw that the heart works constantly, day and night, regardless of consciousness. Pushing about 5 liters of blood per minute, it provides oxygen to every cell in the body. On average, the heart makes about 3 billion contractions.

You know that any muscle, contracting, gradually gets tired, and it needs rest to restore its working capacity. And our heart works around the clock, all our lives.

What task can be set in this lesson, based on the given data?

(Students answer: how does the heart work? Why does it not get tired?)

The teacher poses a problem:

"Why does the heart work throughout life without fatigue?" (Written on the board, students write in notebooks

A problematic question arises: Why can the heart contract throughout life without noticeable fatigue? When does it rest? (Slide 6)
Cardiac cycle.Teacher's story:

The heart works rhythmically. At rest, it contracts 70-75 times per minute. At the beginning, the atria contract - atrial systole, then the ventricles contract - ventricular systole.

With the contraction of the ventricles, the blood is pushed with great force into the arteries, then a general relaxation - diastole.

When the atria contract, the cusp valves are open, when the ventricles contract, they are closed, and the semilunar valves are open. The cardiac cycle consists of 3 phases: I - atrial contraction, II - ventricular contraction, III - general relaxation.

Cardiac cycle.

atrium

Ventricles

Duration

are shrinking

Relaxed

are shrinking

Relaxed

Questions on the class table:

What is the duration of the entire cardiac cycle?
2. How long does the atria work?
3. How long do they rest?
4. How long do the ventricles work?
5. How long do they rest?
6. What conclusion suggests itself from these data? Link the answer to the problematic question.

Heart 04 sec. Works and 0.4 sec rest

Let's work with the itinerary.

Consider Figure 42 on page 81 of the textbook, and complete the table.

(additional task)

phase of the cardiac cycle

Direction of blood flow

Atrial contraction

Sash __________________

Lunar _________________

Contraction of the ventricles

Sash __________________

Lunar _________________

Sash __________________

Lunar _________________

Entry to the itinerary.

Conclusion 2. The heart beats rhythmically. The cycle consists of three phases.

5. Surely, each of you paid attention to how strongly your heart beats when you worry, it’s not for nothing that there are expressions - “the heart is ready to jump out of the chest”, “the heart ran into the heels from fear”, “etc.

4. Influence of environmental factors on the heart.

Among numerous environmental factors, nicotine and alcohol are very bad for the heart.

Message.

Not only these substances negatively affect the heart, but harsh words, evil, injustice hurt the heart painfully.

Shakespeare said

Good feet will stumble sooner or later; the proud back will bend; the black beard will turn gray; a curly head will grow bald; a beautiful face will be covered with wrinkles; deep vision will dim; But kind heart like the sun and moon; and even rather the sun than the moon; for it shines with a bright light, never changes, and always follows the right path.

Let's only say kind words to each other. kind word, smile, good mood, sensitive attentive attitude have a positive effect on the heart.

The heart is a special organ. In all ages it has been held in high esteem by poets, how many poems and songs have been written about it. Remember what epithets the heart is awarded with: restless, quivering, noble, fearless, pure, brave, sensitive, generous, gentle, kind human heart.

So what did you learn in class today?

(Today at the lesson we studied the structure and work of the heart.)

Consolidation.

Find the mistake.

The heart is the engine of blood in the body. It is a three-chambered muscular organ located in the abdominal cavity.

Both outside and inside the heart is lined with epithelial tissue.

Inside there is a valve apparatus that provides blood flow in one direction.

The ventricles are not separated by a complete septum, arterial and venous blood is mixed.

The cardiac cycle lasts 0.8 minutes.

test work

We choose one answer from 3 offered.

Question 1. The human heart is located:

Answer 1 in the abdomen;

Answer 2 in the chest cavity on the left;

Answer 3 in the chest cavity on the right.

Question 2. Human heart:

Answer 1 two-chamber;

Answer 2 three-chamber:

Answer 3 four-chamber.

Question 3. The greatest thickness of the muscle wall has:

Answer 1 left ventricle;

Answer 2 right ventricle;

Answer 3 left atrium.

Question 4. Valve between the left ventricle and the aorta:

Answer 1 is lunar;

Answer 2 is tricuspid;

Answer 3 double leaf

Question 5. In the activity of the heart, one can distinguish:

Answer 1 three phases;

Answer 2 two phases;

The answer is 3 four phases.

Question 6 Duration of the first phase:

Answer 1 0.1 s

Answer 2 0.3 s

Answer 3 0.4 s

Question 8. Valve between the right atrium and the right ventricle:

Answer 1 is lunar;

Answer 2 is tricuspid;

Answer 3 double leaf

Lesson conclusion:(students do)

The heart is a hollow four-chamber muscular organ that provides a continuous flow of blood through the vessels. The rhythm of the heart, the alternation of work and rest, tirelessness and excellent performance. What do you think we will study in the next lesson? (The movement of blood through the blood vessels)

V . Homework: work through paragraph 17, pp. 79 - 81, answer the questions.

Solve the problem: knowing the cardiac cycle, calculate how much time in your life the atria and ventricles worked, and how much they rested.

Craft a heart model (optional)

Route sheet

Lesson topic: "The structure and work of the heart"

Position of the heart in the chest

A). The heart consists of ______ chambers

b). Blood flows from the left ventricle

Blood flows from the right ventricle

V). Build a Circuit

Conclusion 1. Blood moves in only one direction: _________________

______________________________________________________________________

Automatism - the ability of the heart to contract rhythmically without external stimuli under the influence of impulses that arise in itself.

Read the article "The Cardiac Cycle" and complete the table.

(additional task)

phase of the cardiac cycle

Valve position (open/closed)

Direction of blood flow

Atrial contraction

Sash __________________

Lunar _________________

Contraction of the ventricles

Sash __________________

Lunar _________________

Sash __________________

Lunar _________________

Remember! The cuspid valves are always open, except for the phase of ventricular contraction, the semilunar valves are always closed, except for the phase of ventricular contraction.

Conclusion 2. The heart works rhythmically. The cardiac cycle consists of ___ phases.

Nervous humoral

Conclusion 3. Nervous and humoral regulation provides adaptation to the body

____________________________________________________________________________

It seems that history has not preserved the name of the author of the “heart”. It is only known that people have been using this symbol for centuries. According to one version, everything went from playing cards, because that is how the suit “worms” is indicated in them.

In reality, the heart is more like a not very even egg in shape, which has a sharp end (it is called the tip) directed to the left, down and forward. This "egg" is somewhat flattened at the bottom at the back - where the heart is adjacent to the diaphragm. The shape of the upper part (base) is quite difficult to explain on the fingers because of the system of large vessels that flow into and out of the heart.

Question 2. Is there a heart on the right?

The conventional wisdom is that the heart is in the left half chest, is not entirely correct. For the most part, the heart is located in the middle, but due to the natural inclination, the apex of the heart protrudes to the left. By the way, there are exceptions to this rule: in some people, the heart is mirrored, that is, with a deviation to the right. This feature is called dextrocardia (literally "right-heartedness"). More often it does not occur independently, but with a mirror arrangement of all internal organs. This congenital feature occurs in less than 1 in 10,000 people.

Question 3. How does the heart work?

The heart is a complex pump consisting of four sections - chambers: atria (right and left) and ventricles (right and left), and the right sections do not communicate with the left. Relatively thin-walled atria are located above, at the base of the heart, and the bulk of the organ falls on powerful muscular ventricles.

The pumping of blood occurs as a result of rhythmic contractions and relaxations of the heart: periods of contraction are called systoles, and periods of relaxation are called diastole.

In systole, the atria contract first, followed by the ventricles, and here's why. Deoxygenated blood from the whole body is collected in the right atrium, which pushes it further - into the right ventricle. He, in turn, pumps blood into the pulmonary circulation - a network of blood vessels penetrating the lungs. Gas exchange takes place here: oxygen enters the blood from the air, and carbon dioxide is released from the blood. The oxygenated blood goes to the left atrium and from there to the left ventricle. This largest and strongest section of the heart pushes blood through the aorta into the systemic circulation - throughout the body, where blood gives oxygen to organs and tissues and takes carbon dioxide.

The branching vessels that carry blood from the heart to its destination are called arteries. The smallest vessels, through the walls of which the exchange of nutrients and "slags" between the blood and organs, are called capillaries. The vessels that carry waste blood back to the heart are veins.

Question 4. Why doesn't blood flow in the opposite direction?

In order for the blood to flow in the right direction, each section of the heart is separated from the neighboring one and from the vessels by strong connective tissue valves that allow blood to pass only in one direction.

Conditions in which blood seeps back through closed valves are called congenital or acquired. valvular defects hearts.

Question 5. Why does the heart beat?

When the heart "beats" rhythmically, its divisions contract and relax, thanks to the electrical system of the heart. Branching fibers are located on the surface of the heart. They can generate and transmit electrical impulses.

"Signals" originate in the sinus node (it is also called the pacemaker), located on the surface of the right atrium. From the sinus node, the impulse passes through the atria, causing their contraction, and spreads through the ventricles, harmoniously contracting their muscle fibers. In a healthy person, the frequency of contractions is at rest from 60 to 80 per minute - this is the normal pulse.

By the way, it is the activity of the electrical system that is recorded on the electrocardiogram (ECG). It shows how the impulse originates and spreads through the heart, as well as whether there are violations of these processes.

In case of malfunctions in the electrical system of the heart - arrhythmias or blockades - its synchronous work is disrupted.

Question 6. How does the heart work all its life without stopping? Where does it get energy from?

The cessation of blood supply causes the death of the body, so the heart has to work without stopping. However, nature also took care of rest for the hardworking "pump". The heart rests during diastole - in those fractions of a second that pass from the moment the heart relaxes to the next contraction.

Of course, such hard work with such a symbolic rest requires a lot of energy - that is, "enhanced nutrition". From the pumped blood, oxygen and nutrients cannot enter the heart muscle, so the heart, like any other organ, has its own blood vessels.

Question 7. What is a heart attack?

Due to the continuous work that requires a lot of energy, the heart muscle is very sensitive to lack of blood supply. If the lumen of the coronary arteries is narrowed by atherosclerotic plaques, under load, the heart receives insufficient oxygen and begins to get very sick: an angina attack occurs, and this disease is called coronary heart disease.

When the plaque is destroyed, a blood clot forms in its place - a thrombus, which completely blocks the lumen of the vessel. Deprived of nutrition, the area of the heart muscle supplied by this vessel quickly dies off - myocardial infarction occurs.

If the heart does not lose its ability to contract after this, and the person continues to live, the muscle fibers in the infarct zone do not recover, and a scar appears in their place.

Question 8. Why is an electric shock given during cardiac arrest?

Suppose the heart has stopped, or ventricular fibrillation has set in - a condition in which individual muscle fibers do not contract synchronously, but “haphazardly”. In both cases, the electrical system of the heart fails. To resume its work, with the help of a defibrillator device, a powerful electrical impulse is passed through the chest through the heart. It causes all fibers of the heart muscle to contract at the same time, which helps the pacemaker regain control of the heart. Or does not help - it depends on the cause of the violations ...

This effect is much more effective in fibrillation than in cardiac arrest. Therefore, when stopping, adrenaline is often injected first to cause fibrillation, and then a normal heart rhythm is restored with a current discharge.

Address: Russia, Moscow, Novinsky boulevard, 25, building 1, office 3

Questions about human blood

Why does blood flow continuously, although it is ejected from the heart in jerks?

Blood first enters the so-called distensible vessels - large arteries, aorta and pulmonary trunk. When the heart ejects blood under high pressure, their walls, which have many elastic fibers, are able to resist excessive stretching. When the contraction of the heart ends and its relaxation occurs, further movement of blood occurs due to the collapse of the elastic walls of large vessels, like stretched rubber bands. This ensures the continuity of blood flow through the vessels, although it comes from the heart in jolts. In the arteries more distant from the heart, the force of the cardiac impulse is not enough to further move the blood. Muscle fibers predominate in the wall of these vessels. They are called "vessels of resistance" - arterioles.

Muscle fibers in the walls of arterioles are circular, so they are able to contract intensively, resisting blood flow, and move it into the capillaries. Also, the cause of the movement of blood through the vessels is different pressure in them. As blood vessels move away from the heart, the pressure in them decreases.

The human heart acts like a "simple pump", making about 70 rhythmic contractions per minute at rest and pumping about 5 liters of blood. For 70 years of human life, it pumps about 150 thousand tons of blood. This amount of liquid can fill a column of tankers with a length of more than 100 km. The heart performs this intensive and continuous work without a single stop "for repairs". The cycle of cardiac activity consists of three phases: atrial contraction, ventricular contraction, and a general pause. The first phase lasts 0.1 seconds, the second - 0.3 seconds and the third - 0.4 seconds. During a general pause, both the atria and ventricles are relaxed. During the cardiac cycle, the atria contract for 0.1 seconds and rest for 0.7 seconds; the ventricles contract for 0.3 seconds and rest for 0.5 seconds. The alternation of periods of contraction with rest explains the ability of the heart to work without fatigue throughout a person's life.

Why does blood appear on the skin with any scratch?

Everyone knows that the skin is very abundantly supplied with blood vessels. Any wound causes bleeding, because how not to injure those 20-60 capillary loops that are contained in 1 mm: skin surface. Capillaries, like the roots of trees, bushes and grasses, are closely intertwined with each other and have grown into all parts of our body in a dense network.

But we also have very large vessels superficially located (in the region of the eye sockets, temple, nose, jaw, neck). Their injury is very dangerous. The loss of about 2 liters of blood can be fatal for a person.

One drop of blood contains about 5 million red blood cells - erythrocytes. In total, 5 liters of circulating blood contains an astronomical number of erythrocytes - 25 billion. If all the erythrocytes are laid in a layer in one cell, they will occupy an area of 3800 m2.

Red blood cells give blood a cut color, because they include hemoglobin, the combination of which with oxygen has such a color.

Oxygenated blood is called arterial, oxygen-poor blood is called venous.

Articles

heart question

Publication date: 04/15/2011, Modified date: 04/15/2011

SHAPES AND DIMENSIONS

Everyone knows how to draw a heart. Is it really like that?

The real organ, although it resembles its artistic representation, is clearly from afar. It looks more like a bell pepper, and even richly covered with adipose tissue.

The dimensions directly depend on the complexion of its owner: for a short and thin person - about the size of a fist, for a hero - like four.

Unlike many other organs, the heart lives in a separate living space, being separated from its neighbors by the pericardium (earlier it was called the "heart shirt"). Between the sheets of the pericardium and the heart is about 50 ml of fluid - a kind of lubricant that prevents the formation of "heart callus". When they say to you: “I have a callus on my heart from you,” feel free to send someone who blabbed out to EchoCG (ultrasound of the heart) - maybe the person’s pericardial fluid has dried up.

BEAT AND ROCK 'n' ROLL

Why does it not get tired of beating and does it smoothly?

The heart beat ensures the presence of autonomous nodes that create electrical impulses and a developed conduction system. Their task is to generate electricity throughout their lives, which they successfully do using the multidirectional movements of ions in their work.

There are 2 main nodes in the cardiac hierarchy. Sinus supports a rate of 60 to 90 beats per minute - and more if required. Below it is the atrioventricular, which takes control if the sinus fails, and sets the frequency to about 50 beats per minute.

If it also breaks, then the conductive fibers of the ventricles themselves save themselves - the heart makes from 30 to 40 beats per minute, and this is enough to support life.

Reverse insurance also works - if for some reason the sinus node begins to create 200–300 impulses per minute, its lower “colleague” will only let every second impulse into the ventricles, and the organ will be protected from the exorbitant rate of contractions.

Sometimes the rhythm gets off for one reason or another, the beat turns into rock and roll, and an arrhythmia begins.

VIENNA-RIVER

Why does blood only flow in one direction from the heart?

Everything is very simple - it is prevented from changing direction by a system of valves, which, like gates, open only in one direction. There are four of them - aortic, mitral, tricuspid and pulmonic valve.

When a therapist meticulously listens to your heart with a stethoscope, he evaluates their work. Sometimes, from birth or under the influence of diseases, the work of the valves is disturbed, the blood begins to flow not only there, but also back. As a result, the heart is overloaded, its cavities expand, and arrhythmias, heart failure, and other serious complications can occur. The main assistant to the ear therapist in this case is Doppler echocardiography.

VISCERUM INVERSUS

Not exactly on the left, as is commonly believed, rather - in the middle. But still, most of the organ is located on the left side of the chest. But there are people who have it on the right. Most often this happens within the framework of a rare congenital syndrome- situs viscerum inversus (mirror arrangement of organs). This does not threaten the owner of an exclusive with anything dangerous, and often people for a long time they don’t even realize that their organs are located the other way around. And if the paired kidneys or lungs do not care who is on the left, who is on the right, then the heart and liver at one of the physical examinations finally give out a rare diagnosis.

ORGAN-WORKAHOLIC

Why does the heart never get tired and work all its life?

Aspiring medical journalists consider this question their benefit. However, if you think about it, it turns out that the lungs, and the brain, and even the kidneys also work all their lives. And if the brain seems to be resting at night (but in fact it is just doing other things), then we breathe all the time. In general, almost all of our organs are working on a very tight waste schedule day after day.

And the constant work of the heart is provided by nodes that create electrical impulses, and the unique structure of the heart muscle, which, unlike others, cannot get tired. Nature simply threw out the fatigue phase from the cycle of myocardial work. Everything ingenious is simple.

MORE DISCHARGE

Why is electric shock used during resuscitation?

Often during clinical death, the heart does not begin to beat, but flutter. This rhythm has two options - ventricular tachycardia or ventricular fibrillation. Chaotic and very frequent heartbeats are not enough to pump blood efficiently. The doctor's task is to give a super-impulse in order to immediately kill all the "harmful" electrical impulses. After such an electric shock, the heart clean face will begin to create normal impulses and contract correctly.

But the picture familiar to everyone from films, when a straight line goes across the monitor, and the patient is defibrillated, is far from life. They never do that.

The secrets of the heart were revealed by Fedor Yuryev, a cardiac surgeon

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Why does the heart work all its life without getting tired?

Because half of its life it rests

Heart work \u003d 0.4 sec contraction (atria 0.1 sec + ventricles 0.3 sec) + general relaxation 0.4 sec

Atria rest 0.7 sec

The ventricles rest 0.5 sec

It follows from this that the heart rests for most of its life.

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Why is the wall of the left ventricle larger than that of the right? 6) Why does the heart work constantly without getting tired? URGENT AT LEAST A FEW QUESTIONS!

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Why does the heart work all its life without getting tired?

The heart muscle is a special muscle. First, there are many more “muscle fuel” organelles in heart muscle cells, that is, creatine phosphate and adenosine triphosphoric acid, than in skeletal muscle or in smooth muscle. This allows the heart to tire. Secondly, the heart muscle has its own little "brain", nerve nodes. Other muscles are controlled from spinal cord. Because of this, the heart acts very precisely and economically. As soon as a person moves his fingers, the blood flow to the muscles that set them in motion will immediately increase. Try an experiment. Count your pulse while standing for 10 seconds, sit down and count your pulse again for 10 seconds. The pulse will immediately become slower. Thirdly, the heart muscle has time to rest, since it is not always in a contracted state, but relaxes. It is during this relaxation that she rests.

Well, I think in order for it to work perfectly and for a long time, you need to monitor its health regularly, that is, visit a doctor sometimes and keep healthy lifestyle life. Sometimes take pictures of his well-being and drink vitamins for his better work. In general, the principle is the same as with car maintenance. We do everything on time and do not overload the engine with excessive loads (heart). But again, everything is not forever and following such simple rules, we will only extend the life of our heart!

The heart gets tired, but over the years and sometimes you need to let it relax, that is, let's say sleep and rest more often!

Because it is the strongest muscle organ, and if it gets tired, there will be problems.

Why does the heart not get tired and should not rest like other muscles?

The human body is made up of three types or groups of muscles: skeletal, smooth, and cardiac. Today we will talk about the heart muscles.

Skeletal muscles

Skeletal muscles, or striated muscles, are the muscles that most of us probably imagine. Attached to bones and tendons, skeletal muscles in to a large extent control all voluntary and some involuntary (diaphragm working automatically) movements of the body. Arbitrary movement stimulated by "nerve impulses (action potentials) passing through the motor neurons of the somatic part of the nervous system and innervating skeletal muscle fibers, in which they stop contracting."

Like the heart muscle, skeletal muscles get their energy from the mitochondria. The more mitochondria, the more energy available to the muscles, “since it was not necessary for humans to flex their skeletal muscles during their development for long periods of time, the total volume of skeletal muscle contains on average only 1-2% of mitochondria. However, the energy obtained from them is quite enough for solving such muscular tasks as walking or running.”

In addition to mitochondria, skeletal muscle can also use glycogen (an energy reserve) to fuel its energy potential to produce adenosine triphosphate (ATP), the nucleotide that is the main energy carrier in the cell.

Smooth muscles

Smooth muscles are exactly what they are called. They are smooth, without pimples. Smooth muscles are part of the cells of internal organs (except the heart) and work automatically to help you digest food, dilate pupils and carry out the process of urination.

cardiac muscle

Like skeletal muscles, cardiac muscle is striated. The cells of this type of muscle are connected to each other (stick together) in adhesive contacts, "allowing the heart to contract without tearing the fibers."

The stimulus for contraction of the heart pump is nerve impulses moving along the fibers through intermediate connections. “If individual groups of muscle fibers of the heart muscle contract in a scattered and uncoordinated way, for example, due to a heart attack, the heart loses the ability to make coordinated contractions. This condition is called cardiac fibrillation."

Even though the heart pumps are autonomous, the impulses coming from the nervous system “do go to the heart, but their effect is simply to simulate – increase or decrease – the rate of exponential growth and heart contraction. Even if the nerves are destroyed (for example, in a transplanted heart), the heart continues to beat.”

Cardiac muscle, like skeletal muscle, is powered by mitochondria, but that's not all. “On average, the heart contains about 30 to 35% of the mitochondria. Such a number of energy generators explains why the heart muscle in healthy body has no need to rest: there is always some energy transferred to the muscle by increasing calorie intake.

However, this greater reliance on mitochondria means that the heart also has "a greater reliance on cellular respiration for ATP. Lack of glycogen results in less benefit from glycolysis when oxygen supply is limited. Thus, if something interrupts the flow of blood to the heart, then it can lead to damage and even death of the damaged part. That's what happens in heart attacks."

broken hearts

Despite the fact that the heart seems indefatigable, the strength of the human heart has its limits. A recent study showed that if the heart is subjected to extreme stress, even the healthiest can experience problems.

Heart failure

In 2001, scientists studied cardiac fatigue in tired athletes.

“Ewan Ashley, a cardiologist. deployed a portable heart lab right next to the finish line of the Adrenaline Rush super endurance race in the Scottish Highlands… The winning team. crossed the finish line after 90 non-stop hours of biking, climbing, swimming, rowing, with little to no sleep. After testing their hearts. before and after the 400 km race. The scientists concluded that the hearts of the athletes who finished the race were distilling 10 percent less blood compared to the start of the race.”

However, it should be noted that "the hearts of athletes who showed symptoms of heart failure after the race quickly returned to normal, that is, no permanent damage was done."

irreparable damage

A single instance of severe overload may not lead to serious problems, but recent research shows that consistent training can.

In 2011, the British examined “men who were part of the British national or Olympic team in running or rowing, as well as runners who had completed at least one hundred marathons. 12 people aged 50 and over. as well as 17 people. aged 26 to 40 were compared with a group of 20 healthy men over 50, none of whom were athletes… Each person in these groups had an MRI scan of their hearts that identified very early symptoms fibrosis or scarring in the heart muscle. - a condition that further leads to a violation of cardiac function and, ultimately, to heart failure ... Results. rather worried. None of the younger athletes or older non-athletes had cardiac fibrosis. But half of the older athletes showed some scarring of the heart muscle. Everyone who was found to have such abnormalities was often subjected to severe stress.

However, even scientists studying the effects of intense exercise on the heart muscle agree that "exercise strain has never been big problem. Most people run just to keep fit, and for them sign of mild fatigue is a good sign. There is no doubt that exercise in general is very beneficial for heart health.”

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Everyone knows how to draw a heart. Is it really like that?

The real organ, although it resembles its artistic representation, is clearly from afar. It looks more like a bell pepper, and even richly covered with adipose tissue.

The dimensions directly depend on the complexion of its owner: for a short and thin person - about the size of a fist, for a hero - like four.

Unlike many other organs, the heart lives in a separate living space, being separated from its neighbors by the pericardium (earlier it was called the "heart shirt"). Between the sheets of the pericardium and the heart is about 50 ml of liquid - a kind of lubricant that prevents the formation of "heart callus". When they say to you: “I have a callus on my heart from you,” feel free to send the one who blabbed to EchoCG (ultrasound of the heart) - maybe the person's pericardial fluid has dried up.

BEAT AND ROCK 'n' ROLL

Why does it not get tired of beating and does it smoothly?

The heart beat ensures the presence of autonomous nodes that create electrical impulses and a developed conduction system. Their task is to generate electricity throughout their lives, which they successfully do using the multidirectional movements of ions in their work.

There are 2 main nodes in the cardiac hierarchy. Sinus supports a frequency of 60 to 90 beats per minute - and if required, more. Below it is atrioventricular, which takes control if the sine fails and sets the rate to about 50 beats per minute.

If it also breaks, then the conductive fibers of the ventricles save themselves - the heart makes from 30 to 40 beats per minute, and this is enough to support life.

Reverse insurance also works - if the sinus node for some reason begins to create 200-300 impulses per minute, its lower "colleague" will pass only every second impulse into the ventricles, and the organ will be protected from the exorbitant rate of contractions.

Sometimes the rhythm gets off for one reason or another, the beat turns into rock and roll, and it starts arrhythmia.

VIENNA-RIVER

Why does blood only flow in one direction from the heart?

Everything is very simple - it is prevented from changing direction by a system of valves, which, like gates, open only in one direction. There are four in total - aortic, mitral, tricuspid and pulmonic valve.

VISCERUM INVERSUS

Where is the heart located?

Not exactly on the left, as is commonly believed, but rather in the middle. But still, most of the organ is located on the left side of the chest. But there are people who on right. Most often this occurs as part of a rare congenital syndrome - situsvisceruminversus(mirror arrangement of organs). This does not threaten the owner of the exclusive with anything dangerous, and often people for a long time do not even imagine that their organs are located the other way around. And if the paired kidneys or lungs do not care who is on the left, who is on the right, then the heart and liver at one of the physical examinations finally give out a rare diagnosis.

ORGAN-WORKAHOLIC

Why does the heart never get tired and work all its life?

MORE DISCHARGE

Why is electric shock used during resuscitation?

Often during clinical death, the heart does not begin to beat, but flutter. This rhythm has two options - ventricular tachycardia or ventricular fibrillation. Chaotic and very frequent heartbeats are not enough to pump blood efficiently. The doctor's task is to give a super-impulse in order to immediately kill all the "harmful" electrical impulses. After such an electric shock, the heart, as if from a clean face, will begin to create normal impulses and contract correctly.

But the picture familiar to everyone from films, when a straight line goes across the monitor, and the patient is defibrillated, is far from life. They never do that.

The secrets of the heart were revealed by Fedor Yuryev, a cardiac surgeon

It contracts even at rest over 100 thousand times, and with each contraction it ejects blood into the aorta with such force that it could raise a column of blood by almost 1.5 m. Pumping 150 cm 3 into the vessels with each systole (75 cm 3 from the left ventricle to the aorta and from the right to the pulmonary artery), the heart pumps more than 15 thousand liters of blood per day. It should also be taken into account that during physical activity, the heart significantly increases its work. It can eject into the aorta with one systole more than 150 cm 3 of blood, and the frequency of its contractions can reach an athlete at the finish line of 240 beats per minute and even more. If at rest the heart ejects about 4 liters of blood into the aorta per minute, then for an athlete this minute volume of blood circulation reaches 25 liters in some competitions, that is, up to 3 buckets, and some outstanding representatives had record numbers exceeding 40 liters per minute, or 5 buckets.

The reader, who has not lost his friendship with arithmetic, has apparently already come up with such a figure himself. After all, the previously given highest rates of stroke (one-time) volume and heart rate of more than 150 cm 3 and more than 240 beats per minute, in fact, should have given a minute volume of blood circulation of about 40 liters. However, this happens only in isolated cases. The fact is that record values of stroke volume and heart rate usually do not occur simultaneously. The greatest stroke volume is noted at a heart rate of about 150-160 beats per minute, while at a frequency of 200 beats per minute and above, the stroke volume decreases again, because the heart does not have time to adequately fill with blood for short periods between contractions.

How does the heart cope with its enormous work? We often hear questions like this. The heart, we are told, works continuously, without a minute's rest, throughout life. How does it not get tired? After all, the brain works for 2/3 of the day, and then rests for one third ... Why does the heart not need rest?

People who ask such a question are not a little surprised when they find out that the heart rests, at least more than the brain. However, it rests in the process of work itself. We have already said that each systole is replaced by relaxation, diastole. The heart contracted, worked for 0.3 seconds, and then it rests for 0.5-0.6 seconds. This means that it actually rests almost 2/3 of the time, but it knows how to do it, so to speak, on the job. The brain cannot do this, it accumulates the need for rest for the whole day of continuous tension of the higher centers - our sphere of consciousness. At least a third of the time - he does not pretend to be more - the brain must restore strength.

The heart receives two types of blood at the same time:

oxygen-rich blood from the lungs;

Oxygen-poor blood from tissues.

To prevent these two streams from mixing, the space inside the heart is divided in half by a muscular septum.

The left and right heart chambers, in turn, consist of two compartments: the atrium and the ventricle. At the atrium thin walls, and it almost does not pump blood, but serves as a reservoir. The ventricle has thick, muscular walls and performs the main pumping function.

An industrious network of blood vessels

The circulatory system is responsible for the stable supply of body cells with nutrients and oxygen, as well as for the timely removal of toxic substances from them. To accomplish this task, the human body permeates a complex network of blood vessels with a total length of about 160 thousand kilometers.

With a resting heart rate of no more than 55 beats per minute, the heart is able to pump blood more efficiently than with a resting rate of more than 70 beats per minute.

Blood vessels are classified into three types: arteries, veins, and capillaries. During circulation, blood moves away from the heart through the arteries. Capillaries connect arteries to veins that carry blood back to the heart. Types of vessels vary in size, as well as streams and rivulets that flow into large rivers.

The largest blood vessel - the aorta of the coronary arteries - plays the role of a main tube that comes directly from the heart and supplies blood (through numerous branches) to all parts of the body. The smallest vessels are called capillaries - they are so small that most of them can only be seen with a microscope. Through the capillaries, nutrients and oxygen enter the cells from the blood, and the waste products removed from the cells are sent to the veins. The veins then transport the oxygen-poor, toxic-waste-laden blood back to the heart for purification. On the way to the heart, most of the waste is deposited in the kidneys and subsequently excreted in the urine. Carbon dioxide, another pollutant, is excreted through the lungs.

Over 70 years of life, the heart makes about 3 billion contractions and pumps about a million barrels of blood. This amount would be enough to fill more than three supertankers.

Good chair is important for health

The natural posture for defecation is the squatting position. In this position, the anal area is better straightened and opened. If you're sitting on the toilet, place your feet on a bench or trash can to raise them 15 to 20 cm, creating the effect of a squatting pose. Now raise your arms up and straighten your palms so that the transverse colon can easily empty its contents. Remember to drink 8 to 10 glasses pure water in a day.

Scheme of blood circulation

When the blood (which is now filled with waste products removed from the tissues of the body) returns to the heart through the veins, it is immediately pumped through one of the large arteries to the lungs.

There, the blood is released from carbon dioxide and absorbs the life-giving oxygen that is in the lungs. After that, the freshly oxygenated blood returns to the heart to be sent again through the aorta to all parts of the body.

EXERCISE TO ELIMINATE THE LAST DROP

It helps men and women maintain the tone of the muscles of the urethral sphincter. During urination, stop the stream six times by tensing and then relaxing the sphincter. It is recommended to perform twice a day, especially after 40 years. This simple exercise works wonders.

The scheme of blood circulation is quite complex. It resembles the number 8. There are two practically independent circles of blood circulation, through which blood leaves the heart and returns to it again. In a large circle, it goes to tissues, limbs, internal organs and back to the heart. In a small circle, it passes only through the lungs and immediately returns to the heart. The pressure in the blood vessels is different, and in the arteries it is naturally much higher than in the veins, since the arteries carry the blood that the heart pushes out.

A healthy heart beats evenly and rhythmically

The lower part of the heart is slightly shifted to the left side of the upper body, so its beat is easier to hear on the left side of the chest. In fact, the process of contraction of the heart begins in the middle of the neck and goes down deep into the chest. The advice not to sleep on your left side, because this position squeezes the heart, is complete nonsense. The best sleeping position is on your back.

A healthy heart pumps blood in a steady rhythm of contractions called the pulse. Usually the pulse is measured at the wrist, where one of the main arteries lies close to the surface of the body. For an adult, a heart rate of 60-72 beats per minute is considered normal. After each contraction, the heart pauses for about 1/6 second. Consequently, if a person lived for 50 years, then during this period his smart heart spent about eight years on rest.

A well-functioning excretory system is vital to your health and longevity!

The heart has its own thinking brain

We often hear the phrase: "I feel in my heart that this is true." Therefore, our heart is more than just a pump. It can beat on its own, without any connection with the brain. In a human fetus, it begins to form before the brain! Scientists do not know what drives this self-functioning mechanism. There are new, truly revolutionary results of heart research. Researchers at the Heart Mathematics Institute in Boulder Creek discovered that the heart has its own own brain and nervous system. In the 1970s, scientists at the Fels Research Institute found that the brain in the head obeys the orders of the brain in the heart. The heart sends complex signals that affect our emotions, physical health and quality of life! It has the ability to think for itself. The ability of the brain to process information and make decisions is largely dependent on our emotional response to a situation.

These dedicated researchers have discovered a vital connection between the heart and emotions. When the heart responds to emotions such as anger, frustration, or worry, its rhythm becomes unstable, blood vessels constrict, blood pressure jumps, the immune system weakens. Scientists have found that many cases of heart failure were preceded by serious emotional upheavals.

The heart is made up of strong muscles that contract with each beat to pump blood down to the toes and up to the brain.

However, when we experience positive emotions such as love and care, the heart rate becomes smoother, which helps to strengthen healthy connection between heart and brain. Positive heart rate beneficial effect on the activity of the cardiovascular system, restores hormonal balance, strengthens the immune system and the nervous system. When we learn to trust the intelligence of our heart, restore emotional balance, coordinate the work of the heart and brain, we can significantly increase the level of clarity of thinking, physical energy and labor productivity, since our everyday life will become calmer, happier and more qualitative.

The biggest cause of stress is lack of time. According to the American Stress Institute, between 75 and 90 percent of all doctor visits are the result of stress-related disorders. We must use time more wisely and restore balance in our lives. Researchers have found that if we tune in to the positive feelings associated with the heart, such as love, faith, joy, and appreciation, we can achieve greater mental, physical, spiritual, and emotional balance.

The heart rate is especially high in newborns and usually decreases with age, although it may increase again in old age. In women, as a rule, the heart beats a little faster than in men. Resting heart rate can be reduced through exercise, which is important because a slow-beating heart is more energy efficient than a fast-beating heart.

Chapter 3
What is a heart attack?

A healthy heart is the standard of efficiency and perfection. If people don't watch their diet and exercise irregularly, the walls of their arteries become coated with deposits of a waxy, fatty substance called cholesterol. This leads to damage to the arteries, the formation of scar tissue and the further growth of cholesterol and mineral deposits. This condition is called atherosclerosis. Instead of being healthy, flexible, and easily able to withstand the pulsating flow of blood, artery walls become hard and brittle as accumulated deposits narrow the channel through which blood must pass. All this slows down blood circulation and can even lead to the formation of a clot, or blood clot, blocking blood flow.

When a blood clot forms in one of the coronary arteries, it causes a serious condition - coronary thrombosis, or coronary occlusion - and leads to a violation of blood circulation in the part of the heart to which this artery is associated. After some time, the part of the heart that does not receive nutrition and oxygen ceases to function. This is deadly dangerous violation called a heart attack, or myocardial infarction. A condition called coronary artery disease develops when potentially deadly plaque builds up in the arteries, blocking blood flow.

A healthy open artery is an artery clogged with cholesterol in these pictures. normal artery in cross section (1) and an artery affected by atherosclerosis, in which the channel is partially blocked (2).

People pay thousands of dollars each year for labor-intensive tests to find out how high their risk of developing heart disease is. However, experts believe that paying for fresh vegetables, fruits and health club memberships is much more profitable than for any laboratory tests. People who eat low fat and high healthy foods of plant origin, do not smoke, exercise regularly, and keep their weight and blood pressure within normal limits, the likelihood of heart failure is much lower than those who do not, despite exposure or genetic predisposition to heart disease.

Harvard Health Letter

Heart Information from Dr. James Balch

Angina is pain or a feeling of tightness or pressure in the chest. This is a signal that warns of the threat of a heart attack. The pain can be either mild or severe.

Arrhythmia is an electrical instability of the heart that disrupts the natural rhythm of its contractions. The result is palpitation, or a feeling of trembling of the heart. It seems to a person that his heart skips beats. Studies show that magnesium can restore the rhythm of heart contractions and save the lives of patients.

Cardiac arrest occurs when the heart stops beating. Blood stops flowing to the brain, and the person loses consciousness. The reason for such stops is often asymptomatic coronary heart disease. Symptoms of cardiac arrest are dizziness followed by loss of consciousness.

Congestive heart failure occurs when the heart is unable to pump blood efficiently, resulting in fluid buildup in the lungs, difficulty breathing, and swelling in the lower extremities.

Atrial fibrillation is a type of arrhythmia, expressed in palpitation of the heart and rapid heartbeat. Often accompanied by dizziness and fainting.

A myocardial infarction, or heart attack, occurs when a blood clot blocks a coronary artery. As a result, the heart stops receiving nutrients and oxygen, which leads to serious damage to the heart - the death of a section of the heart muscle.

Bragg's books put me on the path to health.

James Balch

Coronary artery disease is caused by atherosclerosis, in which fatty deposits on the walls of arteries prevent blood flow to the heart. In those who suffer from chronic ischemia, some parts of the heart muscle may die. The disease can lead to angina pectoris, myocardial infarction, arrhythmias, or congestive heart failure.

An ischemic stroke occurs when a blood clot blocks either the carotid artery or one of the small arteries that branch from it. Miraculous results are shown by the thrombolytic drug TPA (tissue plasminogen activator). If given within 3 hours of an ischemic stroke, it destroys and dissolves blood clots in 71 percent of patients! Quick Diagnosis has symptoms of a stroke crucial for recovery!

What is a stroke?

As a rule, a stroke occurs for the same reasons as a heart attack. As a result of the accumulation of deposits of cholesterol and minerals, the arteries narrow and clog, which interferes with the free flow of blood. famous saying"A man is as old as his arteries have grown old" is entirely true and should not be lightly brushed aside!

The pressure of the blood trying to force its way through bottlenecks further irritates the walls of the arteries and creates favorable conditions for the formation of blood clots. Breaking away from the wall of the artery and entering the bloodstream, a clot, or thrombus, can slow down or completely stop the movement of blood. If a complete blockage occurs in the vital arteries that feed the heart muscle, a heart attack or coronary thrombosis can result. Cerebral thrombosis (cerebral infarction - the most common type of stroke) occurs when a blood clot blocks one of the arteries that deliver blood to parts of the brain. An intracerebral hemorrhage is a type of stroke that occurs when an artery in the brain bursts and floods the surrounding tissue with blood. Subarachnoid hemorrhage is characterized by bleeding within the brain and bleeding between the internal and outer layers tissue covering the brain. Transient ischemic attacks significantly reduce blood flow for only a few minutes and do not cause long-term consequences. Massive ischemic strokes cause paralysis, impaired speech, and potentially death. The main risk factor is high blood pressure.

I have seen partially paralyzed people who were brought into hyperbaric oxygen chamber, after the first session often went out on their feet!

David Steenblock

After a stroke, blood flow to the affected part of the brain is reduced or completely stopped. Deprived of oxygenated blood, the nerve cells in this part of the brain cannot function, and the part of the body they control also fails. The brain starts to die. This can seriously affect the patient's ability to move and talk. Which parts of the body are affected by a stroke depends on which areas of the brain are damaged and how severe and extensive the damage is.

Strokes are the leading cause of disability and death among women over the age of 50. In addition, they can cause paralysis on one side or part of the body. A mild stroke can cause difficulty moving your arms or legs, speech problems, or memory loss.

Thousands of people fall victim to stroke every year. Although strokes are often associated with advancing age, they do not only affect the elderly. Unfortunately, they have become all too common among people in their 30s and 40s.

On the importance of rehabilitation after a stroke

After a stroke, damaged nerve cells may recover or other brain cells may take over their functions.

Stroke can be prevented through lifestyle changes, health education and good practice. This is the most best protection from stroke and any heart problems. Recent studies suggest that the antibiotic minocycline administered within 6 to 24 hours after a stroke may prevent or mitigate severe impairment in the subsequent period. Minocycline helps relieve the effects of a stroke by inhibiting the activity of white blood cells that can damage the brain and blood vessels.

Some victims are so seriously injured that even partial restoration requires a lot of effort. It is very important to immediately pay due attention to proper nutrition and exercise. We have witnessed truly miraculous cases in which stroke victims regained full control of the affected muscles. To help the rehabilitation process and speed up recovery, start using such important funds wellness, such as speech training, massage, physiotherapy and hyperbaric oxygen therapy, are needed as soon as possible! Prolonged inactivity weakens blood circulation and makes recovery difficult. If a person wants to return the affected areas to a healthy state, he can independently massage them 4-6 times a day (even if only one of them obeys him). And then a miracle will happen!

How to recognize the symptoms of a stroke

Have the person complete three simple tasks:

1) SMILE;

2) SAY a simple sentence;

3) raise both hands up and stick out your tongue. If the tongue is crooked or falls to one side, then this is a sign of a stroke. If the person has problems with ANY of these tasks, call 911 IMMEDIATELY and describe these symptoms to the dispatcher. If a cardiologist or neurologist manages to get to the patient within 3 hours, then the consequences of a stroke, as a rule, can be completely eliminated.

Prevention is much better than cure!

In addition, she is always more successful. This is why we strongly recommend the Bragg Healthy Lifestyle. You need to get out of your head the idea that only age worsens the health of the heart and blood vessels. Remember that age does no harm. This is not a force, but a system of units of measurement. Live in such a way that you do not have to become a victim of a stroke or heart attack. You know perfectly well who your enemies are - tobacco, overweight, stimulants (coffee, tea, alcohol and carbonated drinks), fatty foods, sugar, table salt, lack of daily exercise. Start fighting them right now!

What is angina? Serious warning!

This condition occurs when in one of the heart arteries, temporarily deprived of blood and oxygen, a spasm of the muscle layer occurs, causing acute pain in the chest! This pain, called anginal pain, is the most common symptom of heart disease, especially in women.

Sometimes heart attacks are strong and sudden, and sometimes they develop slowly.

Studies have shown that in women, chest pain is twice as likely to be the first symptom of a sudden heart attack (*Women may have different warning symptoms.). This is the warning pain experienced by the heart, desperately urging its owner to change their lifestyle - go on a healthy diet, fast, exercise, etc. Usually, such spasms last only a few seconds, but sometimes can increase to 3-5 minutes. and in rare cases exceed 15–20 minutes. This is a serious warning! Please pay attention to the signals listed below!

Warning signs of heart problems

Pain or discomfort in the chest, abdomen, back, neck, jaw, or arms may indicate insufficient blood and oxygen supply to the heart muscle with potentially serious problems such as atherosclerotic plaques in the coronary arteries.

Nausea during or after exercise can be caused by different reasons, but may also indicate a violation of cardiac activity.

Unusual shortness of breath during exercise can be related to respiratory conditions (asthma, etc.) but can also be a sign of heart problems.

Dizziness or fainting may be signs serious problems and require immediate medical attention.

Intermittent pulse. If you notice that your heart is beating irregularly, tell your doctor.

Too much rapid pulse at rest. If your resting heart rate is 100 beats per minute or more, tell your doctor.

Why does the heart need oxygen?

As you well know, oxygen is an essential necessity for human life. Of all the oxygen you breathe in, only one-tenth gets to your heart. But it uses this oxygen much more efficiently than any other organ in the body. 80 percent of all the oxygen that enters the heart is completely utilized by it, the degree of efficiency of oxygen consumption in the heart is three times greater than in any other organ of the body.

It will be logical if you ask why the heart needs oxygen and what it does with this oxygen. The heart needs oxygen so that its muscle fibers can periodically contract. As you have already learned, the heart is a muscular organ. Cardiac muscle fibers are arranged in several layers, in which they run longitudinally or circumferentially, circularly. When muscles contract, blood is pushed out of the heart into the vascular system. If you could look inside your heart, you would see that it is made up of four cavities. Two are located at the top, they are known as the atria. The two lower cavities are called the ventricles. The ventricle and atrium are separated by peculiar cusps - valves, thanks to which the blood inside the heart can move in only one direction: from the atrium to the ventricle. The left and right atria and ventricles are separated by a common muscular wall. It prevents the blood from mixing: the one that goes to the lungs to receive oxygen there, with the freshly oxygenated blood that goes from the lungs to other parts of the body.

Now it becomes clear that the heart is just a kind of double pump. What happens when the blood flowing from the organs of the body enters the right atrium and then flows into the right ventricle of the heart? When the heart contracts, blood from the right ventricle rushes to the lungs, where carbon dioxide is removed from it and oxygen is supplied from the air. From the lungs, blood enters the left atrium, and from it - into the left ventricle, from where, with the contraction of the heart, it is pumped to all other organs of the body through the arterial system. The valves between the atria and ventricles, when the ventricles contract, prevent blood from flowing into the atria, so all the blood from the ventricles is pushed into the arteries.

Despite the fact that the heart has only one function, namely to pump blood, it has to pump two different blood compositions. One blood is bright red. This is oxygenated blood. The other darker colored blood is the blood that comes back from the body and is filled with carbon dioxide. A common misconception is that arteries always carry "fresh" blood, while veins carry "used" blood. This is not entirely true, since arteries always carry blood FROM the heart, while veins return blood TO the heart. Therefore, the blood delivered from the heart to the lungs is “used” blood that needs to be enriched with oxygen and flows through the arteries. The same applies to the freshly oxygenated, bright red blood that flows from the lungs to the heart and is carried through the veins.

What do heartbeats say

How about your heart sounds? You may have heard with a stethoscope the sounds that your incessant pump makes. If so, what you remember probably sounded like "llab-dub". The second dub sound is shorter and slightly higher than the first. The first sound is made by a valve that closes between the atrium and the ventricle to prevent the blood from flowing backwards, and the noise is produced by the contraction of the muscles, which at the same moment release blood from the lower cavity. The second sound is produced by the closing valves of the arteries, which carry blood from the right side of the heart to the lungs and from the left side of the heart to other organs, valves that prevent blood from returning back to the heart.

The knock is not regular: one-two, one-two. There is a pause between each llab-dub. During this pause, which lasts less than a second, the heart rests. This occurs between the moment when the ventricles are partially filled with blood and the next portion of blood begins to flow into the atria.

And so the heart continues to beat, producing about seventy to eighty beats per minute, the heart rate increases during intense physical exercise or at the moment strong emotions. And it never rests, except for that pause between beats. It is rather strange that this pause is longer than the time of the contraction of the heart, its active work. However, it is not long enough to allow the heart to relax to the same extent as other muscles in the body do. Since the heart beats more than sixty times a minute, it becomes clear that full cycle activity of the heart takes less than one second. With each contraction, the heart pushes about a hundred milliliters of blood, which keeps the body alive. This amount of blood is enough to fill a small wine glass. These one hundred milliliters make up only about 1.5 percent of all blood in the body. Then you can calculate that every drop of blood in the body manages to pass through the heart at least once a minute. And this fact becomes even more intriguing when you realize that if all the blood vessels in your body were tied end to end into one long vessel, then it would stretch for 115 thousand kilometers, a length sufficient to tie around the Earth three times.

Pushing the blood to do your thing

What about all these vessels that carry blood? They are just conductors of life important fluid? This again shows the general delusion, because everything is not so at all. The blood vessels show a tremendous ability to adapt to different conditions, but they also have some freedom of action. There are three types of blood vessels: arteries, veins, and capillaries. Most a large percentage The blood vessels of the body are accounted for by the capillaries. Indeed, the capillary system is so large that it could provide the flow of all the blood of the body, and this is about five liters. However, only one part of the capillary system functions in any certain moment time. The system of capillaries is such that it can open or close first in one part of the body, and then in another. Therefore, those tissues that require more blood, - such as the muscles of the arms and legs - have a more extensive capillary system than tissues in other parts of the body, which are not as active. At the moment of increasing activity of an organ, more capillaries open in it.

Arteries are the main main overpasses of the body. They are elastic tubes made of muscle fibers, slightly wavy on the inside and densely coated on the outside. These tubes are able to expand and contract so as to pass the amount of blood required by the body at a given time and at the appropriate pressure. The contraction of the arteries, as well as their relaxation, helps the pumping work of the heart to such an extent that the blood can move throughout the body and maintain normal pressure. This pushing movement of the arteries coincides with the rhythm of the heart, so you can count the frequency of its contractions (pulse) without a stethoscope, only by checking the pulsation of the arteries in the place where it is palpable (for example, on the wrist).

The main artery of the heart is known as the aorta. Many other arteries leave this main duct - the large ones go to the head, arms, legs and other large organs. The vessels that carry blood from arteries to capillaries are called arterioles. They are barely visible without a microscope, and are connected to the capillary system to such an extent that if all the blood vessels of this system open at the same time, they will contain all the blood of the body, as already mentioned before. In addition, a single capillary is so small that the red blood cells that carry oxygen throughout the body must pass through it in turn. Red blood cells are quite small, so small that a thousand blood cells stacked on top of each other would not take up even a centimeter in height. The walls of the capillaries are quite strong - strong enough to prevent blood from seeping through them into the tissues. On the other hand, white blood cells - disease fighters - which are also present in the blood, and even a small amount of fluid, can leave the bloodstream, passing through the narrow spaces between the cells that make up the walls of the capillaries. Therefore, blood flows through the capillaries very slowly. In fact, it takes a full minute for the blood to move 1 centimeter through the capillary tube - compare with blood moving through the arterial system at a speed that reaches 60 kilometers per hour.

During this slow journey through the capillary system, oxygen and nutrients that are required by the cells of the body exit the tiny blood vessels and feed the tissues. Lymph also passes through the walls of the capillaries - a liquid that bathes tissue cells. Capillaries allow other blood components to seep through themselves if it is necessary to restore tissues and maintain them in working condition. At the same time, waste products, chief among which carbon dioxide, on the contrary, enter the capillary from the tissue, are picked up blood stream and swept away to get rid of them when the blood reaches the lungs again, or the liver, or the kidneys.

The blood can move up

This wonderful circulatory system has one more amazing property. Have you ever wondered how blood, moving back to the heart and lungs, travels up the body? It is logical to conclude that blood from the upper body can flow down from the capillaries through the veins and then to the heart to be filled with oxygen in the lungs. But what about the blood that has completed its nourishing and restorative journey to the feet or to any other parts of the body located below the level of the heart? Amazingly, nature has created two completely unique ways upward movement of blood. The first of these is due to the fact that the veins are located between the muscles. The other is that veins have a built-in valve system that prevents blood from flowing back and helps it move straight to the heart. If you look at the veins in your legs, you will see that they wrap around the muscles. Every time the muscles contract, they compress the veins, pushing the blood closer to the heart because the valves prevent it from moving backwards. This explains, for example, why you may suddenly feel tired or lethargic if you have been standing in one position for a long time or sitting still for a long time. The blood in the lower part of the body does not receive required amount shocks from the muscular system and therefore does not reach the heart. This is the cause of the varicose veins veins. The veins lose their elasticity or the valves in them begin to malfunction just because they are rarely used. And then there is stagnation of blood, which leads to the expansion of the veins.

Now you will certainly agree that the cardiovascular system really wonderful mechanism. But that's not all: there are other wonderful things that this system can do. For example, if for some reason the arteries or arterioles that feed a small area of the body (or even a large part of it) stop functioning, neighboring vessels take on the burden of their work. From different directions, the tissues, over which the threat of loss of blood supply hangs, will receive fresh blood from other arteries that did not supply this area before. In fact, these arteries often grow very quickly and become thicker and longer to take on the job of carrying blood. Sometimes they do their job with the same efficiency as the arteries they replaced, and even more often you do not even notice the changes that have taken place in your body.

All of this is vital because the body is made up of millions of cells, all of which are nourished through the blood. They are the most loyal consumers, they require continuous supplies, and your faithful heart satisfies their requirements, from your birth until the day it goes out the last "llabdub".

The heart is therefore the central motor complex mechanism, which is so well designed that most people have it running smoothly for their entire lives. And precisely because it is so well designed, it always has power reserves that can be used in case of emergency. It is so well-organized that it can almost always repair itself quickly and efficiently. Perhaps this miracle will become more understandable if we try to imagine a car running perfectly for seventy years without much maintenance, apart from the periodic supply of fuel and water! If you have a car, then you take good care of it. And if you are a normal motorist, then at the first sign of wear and tear, you will begin to repair it. What's more, you can even go out and buy a new one if the old one can't function as intended. On the other hand, if your heart is malfunctioning after forty or fifty years of neglect, then you will not be able to go and buy a new one. And you panic because you didn't pay as much attention to it as you did to your car. You must realize that your heart is very much like a car. It requires - in its own way, of course - at least the same amount of attention that you spend on your car.

Causes of cardiovascular disease

In the United States, two people die every minute due to cardiovascular disease. Heart disease has become the leading cause of death for people over the age of thirty. But what are these diseases? And what causes them?

People always talk about those who have heart problems. You may hear words such as "cardiac", "heart disease", "heart disease", "rheumatic heart", "angina pectoris" and many other terms, some of them sound scientific, while others are no more scientific than phrase "heart attack".

Almost everyone can easily guess that all these terms refer to a diseased heart. But lack of knowledge about this most important of all organs - especially at a time when half of all deaths are due to cardiovascular disease - can cause unjustified fears in some people. On the other hand, it may lead another part of the people to the fact that they will not take simple safety measures that could save their lives.

Research carried out in different countries around the world have identified many possible causes of heart disease. Some scientists believe that there is a special type of people who are predisposed to cardiovascular disease. Some theories claim that heart disease is inherited, others that "enterprising" people are potential victims of heart disease, or that physical inactivity is the basis of heart disease, or that fear and anger can cause a heart attack, that some species drinking water are the cause of disorders in the work of the heart, that viruses can also be to blame, even social status and economic status can have a significant impact on the occurrence of cardiovascular diseases.

Heart disease strikes without warning

Unfortunately, even the most thorough examinations cannot predict the occurrence of certain heart diseases. A heart attack can happen completely unexpectedly, and anyone can be a victim. It is not difficult to put your car in the garage and check everything in it. The mechanic can say that the car is in excellent condition and does not need any repairs. But a small amount of dirt can get into the gas tank. After twenty-four hours, this dirt can reach the tube that leads to the motor. Dirt can plug it, and gasoline will not pass through the pipe. The motor will stall. This is what sometimes happens during heart attacks when they happen unexpectedly. In addition, there is no way to predict exactly when this might happen. A blockage of a blood vessel that feeds the heart muscle is called thrombosis of the coronary or venous vessels, and what the vessel is blocked with is called a thrombus. As a result of lack of oxygen and nutrients myocardial infarction occurs, which is accompanied by the destruction of heart muscle cells. This is just one of the most common heart conditions that we know of.

The word "coronary" refers to the arteries that carry blood to the heart muscle from the aorta, the main artery that was described in the previous chapter. There are two coronary arteries, which in turn have many branches that extend to each fiber of the heart muscle. Only these arteries supply the heart with oxygen. Blood enriched with oxygen, after passing through the lungs, before passing through the left atrium and ventricle, does not participate in the nutrition of the heart. But when the blood is pushed out of the heart, some of it goes to the coronary arteries, and it is used to feed the heart muscle itself and its fibers in the same way as it happens in other tissues of the body.

Artery damage can be caused by many things.

Damage to the coronary vessels can be caused by many factors, including aging. This damage is called sclerosis.

The most common type of sclerosis is called atherosclerosis. It is something like deposits that pollute internal surfaces blood vessels, something like rust inside a water pipe. If these deposits are located in small groups, then they do not cause difficulties in the blood flow. But when the groups increase and build on each other in such a way that the vessel becomes narrow, the blood stagnates and thickens, and this causes a heart attack. Atherosclerosis is actually only one of the forms of arteriosclerosis and probably one of the most famous and common forms. Arteriosclerosis is a general name that is used to describe all types of hardening of the arteries, which are caused by thickening of the walls of the vessels, as well as salt or fat deposits in them. With atherosclerosis inner part arteries do not always harden, but the walls of the arteries become thicker and rougher, depositing a fat-like substance known as cholesterol. And as a result, blood clots form.

In fact, atherosclerosis causes three main types of cardiovascular disease. You have already read a brief description of coronary thrombosis, or coronary occlusion (obstruction). This disease occurs when there is a complete blockage of the coronary artery, which in turn usually causes a myocardial infarction, which, as you already know, is the sudden death of a large number of cells in the heart muscle. Pain during such an attack, which does not necessarily occur after physical or emotional stress is always sudden. And it is so strong that it is almost impossible to bear. It is described as pain from a vise squeezing the chest, it can also radiate to the left shoulder, neck and arm. The pain lasts more than a quarter of an hour, but may not go away for several hours. It is accompanied by heart failure, shortness of breath, cold sweat, low blood pressure, and sometimes fever.

When you hear people talking about a heart attack, they usually mean coronary occlusion followed by myocardial infarction.

The second type of common heart disease caused by atherosclerosis is angina pectoris. In fact, angina pectoris is more of a symptom, a warning about the possible appearance of the disease. She says that the resulting pain spasm is caused by a short-term failure in the delivery of blood to the heart muscle.

The cause of this failure may be a temporary spasm of an artery that blocks blood flow, or a sudden increase in the need for more blood. Such an increase is often associated with hypertension, as well as with the aging of the body. And this condition is more common in men than in women.

The pain during such an attack is also quite strong, but usually short-lived. As a rule, it lasts no more than a quarter of an hour and can be caused by physical exercises, emotional outbursts, overeating, and most often anxiety and fear.

The third large group of heart diseases caused by atherosclerosis is acute heart failure. It differs from angina pectoris in that in the case of angina pectoris, a decrease in blood flow is a transient phenomenon. In the case of acute heart failure, the heart muscle experiences "hunger" for a much longer time. Such a lack of nutrition occurs during times of severe physical or emotional stress, that is, when the heart's need for oxygen increases, and its supply does not correspond to the increased need. As a result, very often some muscle fibers die. This condition is more common in men, especially in obese and full-blooded men.

What other diseases are affecting the heart? You often hear about high blood pressure. In a healthy person, the various chemicals produced in the body, as well as the nerves and muscles in the walls of the arteries, work together to maintain normal blood pressure. A sudden confrontation, fear, anxiety, or nervous tension can cause the pressure to rise temporarily. For some people, blood pressure rises gradually over several years. For others, the rise is rapid and continues until it reaches dangerous level. In the case of hypertension, persistently high blood pressure weakens the arteries and therefore overloads the heart. This leads to an increase in the heart and a decrease in the efficiency of its work.

High blood pressure can also damage the body's arteries. It increases the risk of heart attacks, and hypertension itself is potentially dangerous disease, one of those that, for some reason, affects women more often than men.

Everyone knows how to draw a heart. Is it really like that?

The real organ, although it resembles its artistic representation, is clearly from afar. It looks more like a bell pepper, and even richly covered with adipose tissue.

The dimensions directly depend on the complexion of its owner: for a short and thin person - about the size of a fist, for a hero - like four.

Unlike many other organs, the heart lives in a separate living space, being separated from its neighbors by the pericardium (earlier it was called the "heart shirt"). Between the sheets of the pericardium and the heart is about 50 ml of fluid - a kind of lubricant that prevents the formation of "heart callus". When they say to you: “I have a callus on my heart from you,” feel free to send the one who blabbed to EchoCG (ultrasound of the heart) - maybe the person's pericardial fluid has dried up.

BEAT AND ROCK 'n' ROLL

Why does it not get tired of beating and does it smoothly?

There are 2 main nodes in the cardiac hierarchy. Sinus supports a frequency of 60 to 90 beats per minute - and more if required. Below it is atrioventricular, which takes control if the sine fails and sets the rate to about 50 beats per minute.

If it also breaks, then the conductive fibers of the ventricles themselves save themselves - the heart makes from 30 to 40 beats per minute, and this is enough to support life.

Reverse insurance also works - if the sinus node for some reason begins to create 200-300 impulses per minute, its lower “colleague” will only let every second impulse into the ventricles, and the organ will be protected from the exorbitant rate of contractions.

Sometimes the rhythm gets off for one reason or another, the beat turns into rock and roll, and it starts arrhythmia.

VIENNA-RIVER

Why does blood only flow in one direction from the heart?

When a therapist meticulously listens to your heart with a stethoscope, he evaluates their work. Sometimes, from birth or under the influence of diseases, the work of the valves is disturbed, the blood begins to flow not only there, but also back. As a result, the heart is overloaded, its cavities expand, and arrhythmia, heart failure, and others may occur. The main assistant to the ear therapist in this case is Echocardiography with Doppler effect.

VISCERUM INVERSUS

Where is the heart located?

Not exactly on the left, as is commonly believed, rather - in the middle. But still, most of the organ is located on the left side of the chest. But there are people who on right. Most often this occurs as part of a rare congenital syndrome - situsvisceruminversus(mirror arrangement of organs). This does not threaten the owner of the exclusive with anything dangerous, and often people for a long time do not even imagine that their organs are located the other way around. And if the paired kidneys or lungs do not care who is on the left, who is on the right, then the heart and liver at one of the physical examinations finally give out a rare diagnosis.

ORGAN-WORKAHOLIC

Why does the heart never get tired and work all its life?

MORE DISCHARGE

Why is electric shock used during resuscitation?

But the picture familiar to everyone from films, when a straight line goes across the monitor, and the patient is defibrillated, is far from life. They never do that.

The secrets of the heart were revealed by Fedor Yuryev, a cardiac surgeon

When the heart is stuffy

We usually do not feel a healthy heart. It often beats only in moments of strong emotions - from fear or joy, love or hate. It echoes loudly and evenly in the ears during heavy loads - a long run, climbing a steep mountain, at the time of a parachute jump.

And if it suddenly beats for no reason, “died”, “failed somewhere”, if there was a sharp pain in the chest, radiating to the shoulder blade, neck, teeth, the doctor to whom you describe your feelings will immediately suspect coronary disease heart (CHD). This means that your heart does not have enough oxygen, it suffocates.

What is IBS

Ischemia is a lack of blood to the heart muscle (myocardium), which acts as a pump. For the heart to work, the myocardium needs oxygen and nutrition, which blood brings to it through coronary vessels. From the heart, the blood must carry away the "products of combustion." If the lumen of the coronary vessels is narrowed by spasm or sclerotic deposits, there is a lack of oxygen, and there is an excess of "waste" - the myocardium begins to suffocate, weaken. It does not pump blood well, chronic heart failure occurs.

The first form of coronary artery disease is angina pectoris, in which the lumen of the coronary vessels is narrowed, but not completely. Main symptom- pain behind the sternum, radiating to the left arm, under the shoulder blade, left side mandible, even teeth. Angina can be stable or unstable, with exertion and even at rest.

The second form of IHD is myocardial infarction. When one (or more) of the coronary vessels becomes completely blocked, a part of the muscle stops receiving nutrition and oxygen and actually dies. Further, a person's life depends on the size of the deceased part and the speed with which doctors will help him. In Russia, myocardial infarction is the main cause premature death. More than 600,000 Russians die from coronary artery disease every year - a whole Big city.

10 risk factors

objective(unmanaged):

1. Heredity

2. Gender (men get sick more often than women)

3. Age (the older, the higher the risk)

subjective(managed):

4. Violations of fat metabolism, high cholesterol

6. Smoking

7. Violation carbohydrate metabolism, diabetes

8. Overweight

9. Lack of movement (lack of exercise)

10. Psycho-emotional overstrain, stress

How the heart works

The heart is a four-chambered muscular pump, weighing an average of 300 grams. For one contraction, it pushes 60-75 ml of blood into the vessels. During the day, the heart contracts about 100,000 times, pumping from 6000 to 7500 liters of blood or 30-37 full cast-iron baths with a capacity of 200 liters.

Blood moves in the heart in a figure-of-eight pattern: it flows from the veins into the right atrium, then the right ventricle pushes it into the lungs, where it is saturated with oxygen and returns to the left atrium. Then from the left ventricle through the arteries blood flows to all organs of the body. Nutrition and respiration of the heart itself is provided by the coronary (coronary) vessels.

Run Bunny Run

Everyone knows that lying on the couch is more harmful than walking and exercising. And why? The scientists of the Institute of Clinical Cardiology figured it out. The rabbits were placed in cramped cages (almost the size of their bodies) and kept motionless for 70 days. Then they looked at their hearts under an electron microscope. We saw a terrible picture. Many myofibrils - the fibers that make the muscle contract - have atrophied. The connections between cells that help them work together have been disrupted. The changes affected the nerve endings that control the muscles. The walls of the capillaries carrying blood to them began to grow inward, reducing the lumen of the vessels. Here's your sofa!

Why people love Petrosyan and K

Dr. Michael Miller of the University of Maryland and his colleagues conducted a series of experiments by showing volunteers two films: a happy one and a sad one. And at the same time, they tested the work of their hearts and blood vessels. After the tragic film, in 14 out of 20 volunteers, the blood flow in the vessels decreased by an average of 35%. And after the funny one, on the contrary, it increased by 22% in 19 out of 20 subjects.

Changes in blood vessels in laughing volunteers were similar to those that occur during aerobic exercise. But at the same time, they did not have any pain in the muscles, nor fatigue and overexertion, which often accompany large physical activity. Scientists have concluded that laughter reduces the risk of cardiovascular disease.

At broken heart

"Broken Heart Syndrome" - such a new diagnosis has appeared in cardiology. It was first described 12 years ago by Japanese doctors. Now it is recognized in other countries. The syndrome occurs, as a rule, in women over forty who have experienced a love failure. The cardiogram and ultrasound show the same disorders in them as in a heart attack, although the coronary vessels are in order. But the level of the stress hormone - adrenaline, for example, they have 2-3 times higher than in heart patients. And in comparison with healthy people, it is exceeded by 7-10, and in some cases even 30 times!

It is hormones, doctors say, that “hit” the heart, forcing it to react classic symptoms heart attack: pain behind the sternum, fluid in the lungs, acute heart failure. Fortunately, patients with the new syndrome recover fairly quickly if they are treated correctly.

Why are we afraid of cancer and not afraid of a heart attack?

Director of the Institute of Cardiology of the Russian Cardiology Scientific and Practical Complex of Roszdrav Corresponding Member of the Russian Academy of Sciences, Academician of the Russian Academy of Medical Sciences Yuri BELENKOV:

There are two reasons, in my opinion. The first is the myth that cancer is incurable, although now many of its types are successfully treated. The second is that cardiovascular diseases last for a long time, at the initial stage with almost no symptoms. Only a part of such patients (25%) die suddenly, sometimes without even having time to "get sick". The rest live long enough, especially if they receive modern adequate treatment. We have 50 million people suffering from coronary artery disease and hypertension - almost half of the adult population. Approximately 8 million of them are in the deadly stage. Unfortunately, at this stage, the prognosis for life is much worse than in cancer patients. But correct image life, attention to yourself and timely access to doctors allow you to maintain heart health until old age.

6 tips from a cardiologist

Head of GNITs preventive medicine Roszdrav, Academician of the Russian Academy of Medical SciencesRafael Oganov:

- To keep the heart healthy on long years, you must follow a few important rules:

1. Do not smoke.

2. Eat right and varied (meat, fish, vegetables, fruits, cereals, whole grain bread, less fat and sweets) and monitor your weight.

3. Move more, especially in the fresh air: for example, walk at a fast pace for at least 3, and preferably 5 km a day

4. Control your blood pressure. With its steady increase or frequent drops be sure to get tested.

5. After the age of 40, regularly check the level of cholesterol and sugar in the blood.

6. Drink a glass of red wine with dinner two or three times a week.

Although the heart forms two blood pumping systems, its two pumps are not identical. The right side of the heart pumps blood through the nearby lungs. This requires relatively little physical effort compared to that exerted by the left side of the heart, which pumps blood to all other tissues in the body, including the extremities, which are the furthest away from the heart. As a result, the walls of the right side of the heart are much thinner, and the muscles are much less developed than on the left side. In this case, both sides must pump the same volume of blood with each compression, since the amount of blood returning from the system corresponds to the amount that enters the heart on the other side.

The pumping of blood is also carried out in two stages. The first chamber is the atrium. It is separated by valves from the lower chamber, the ventricle, which pushes blood out of the heart. The valves prevent backflow of blood into the atrium when the ventricle is compressed and, because of the difference in force required to operate the two parts of the pump, the walls of the atrium are comparatively thinner and weaker compared to the walls of the ventricle.

The control of muscle contractions in the heart is, of course, a vital point and is provided by the horse's body in two ways. First, there is control exercised by the autonomic nervous system. It ensures that the heart will beat without any effort on the part of the horse. In addition, the strength and heart rate will automatically change according to the needs of the horse. This is achieved by changing the level of adrenaline circulating in the circulatory system. Adrenaline is a hormone produced by the adrenal gland near the kidney and released into the blood stream to change the heart rate and close off those blood vessels that supply blood to non-essential parts of the body. Thus, the heart rate automatically increases when the horse is scared and ready to run away from danger.

We refer to the concept of "release of adrenaline" when describing stress. When muscles perform any work, they need large quantity oxygen, therefore, the heart rate increases accordingly (Fig. 69). However, the heart rate of a galloping trained horse is not the same as that of an untrained horse. Trained muscles produce less waste products and use oxygen much more efficiently, so a trained horse will have a lower heart rate for a given activity level. The horse's respiration rate and post-exercise pulse rate are not a measure of how much work he has done, but rather whether the horse has been trained enough to handle the challenge and whether the heart and lungs have had to withstand the strain. All these factors are automatically weighed every second of a horse's life.

Each individual muscle fiber of the heart must contract at exactly the right time in conjunction with other muscles if blood is to be ejected evenly and efficiently from the atrium, through the valves into the ventricle, and then out of the heart through yet another set of valves. The valves open and close accordingly due to the difference in blood pressure on one side or the other. The muscles of the heart contract as a wave of electrical impulses passes through the heart. Although the voltage of these impulses is measured in millivolts, these electrical charges can be received at a considerable distance from the heart and can be displayed in the form of an electrocardiogram (ECG) (Fig. 70). Violations, and these are usually interruptions of impulses, lead to wrong rhythm hearts. However, heart murmurs are associated with physical abnormalities of the heart valves and, as a result, turbulence in the blood passing through the heart.

Rice. 70. ECG recording.

Passing through the heart and causing muscle contraction

We get the most information about the functioning of the heart when listening to the horse's chest with a stethoscope. The heart sounds that we hear, which are like knock-knock sounds, are not so easy to interpret. In a healthy horse, essentially four types of heart sounds can be heard, two of which are loud and two are quieter than the fundamental tone. Complementary tones are commonly referred to as heart murmurs and are relatively easy to hear, although they are not as easy to interpret. Rhythm disturbances are difficult to detect human ear and only a strong arrhythmia can be determined with a stethoscope.

More recently, it has been possible to look inside the horse's heart through the use of a device called an ultrasonic sector scanner. This device is the result of improvements in those scanners used to detect pregnancy in both humans and horses (Fig. 71).

A moving beam of high-frequency sound signal is passed through the examined part of the body, and the computer uses the reflections from internal structures signals to create their image. Despite the fact that this method has not yet found wide application, it allows you to examine the heart valves on the monitor at the time of the actual heartbeat. This is especially useful in identifying the cause, and hence the significance, of many heart murmurs.

Why is the heart able to work continuously. Heart failure

Kirikov Tatyana Alexandrovna

Question 2. Is there a heart on the right?

Question 3. How does the heart work?

Question 4. Why doesn't blood flow in the opposite direction?

Question 5. Why does the heart beat?

Question 6. How does the heart work all its life without stopping? Where does it get energy from?

Question 7. What is a heart attack?

Question 8. Why is an electric shock given during cardiac arrest?

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The heart has its own thinking brain

Chapter 3 What is a heart attack?

Heart Information from Dr. James Balch

What is a stroke?

On the importance of rehabilitation after a stroke

How to recognize the symptoms of a stroke

Prevention is much better than cure!

What is angina? Serious warning!

Warning signs of heart problems

What do heartbeats say

Pushing the blood to do your thing

The blood can move up

Causes of cardiovascular disease

Heart disease strikes without warning

Artery damage can be caused by many things.

BEAT AND ROCK 'n' ROLL

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ORGAN-WORKAHOLIC

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