The heart - anatomy, function and common diseases

Leading Medicine Guide Editors
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Leading Medicine Guide Editors

The heart, commonly known as the pump, is the central organ of the human body. It serves as a hub for the vital blood flow and ensures the blood supply to the extremities, brain and organs with a rhythmic movement, the heartbeat. It is therefore of crucial importance for the vital functions of the human organism.

Article overview

What is the heart?

The heart is located behind the sternum, the breastbone, and is slightly inclined to the left side. It is a powerful hollow muscle that weighs around 300 grams in its normal state. It regulates the blood supply in the body by regularly pumping blood. The blood pumped throughout the body transports vital substances such as oxygen and nutrients. It is not without reason that the heart is considered by many to be the engine of life due to its indispensability for maintaining the human circulatory system.

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In an average organism, the heart beats around 60 - 90 times per minute at rest. This amounts to over 100,000 beats per day. Approximately 8000 liters of blood flow through the body. Of course, these figures only apply to an organism at rest. During high levels of tension or increased physical activity, the blood transfer increases up to fivefold.

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The heart - structure and function

The hollow muscle of the heart has four inner chambers. The two anterior chambers are called the atrium and consist of the left and right atrium. The larger chamber is called the ventricle and is made up of two sections of equal size. A septum separates the two chambers of the heart.

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As part of the blood circulation, the atrium collects the venous blood before the ventricle receives the collected blood and feeds it back into the circulation. The blood now flows via the arteries to the various regions of the body. Oxygen-poor blood flows into the lungs, oxygen-rich blood into the rest of the body.

Heart valves are located at the openings of the heart muscle and between the atrium and the ventricles, which determine the direction of the blood flow. They ensure that the same amount of blood always flows through the heart. When using a stethoscope, doctors can hear the mechanism of the heart valves and the blood flow they regulate.

The heart itself is also dependent on a sufficient blood supply. To ensure this, it has its own system of blood vessels, the coronary vessels.

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Physiological importance of the heart

The two most important physiological needs of humans are breathing and the consumption of food. Both processes are responsible for ensuring that the organism can provide energy and maintain its vital functions. The nutrients contained in food reach the various parts of the body via the blood. And the oxygen taken in through the air must also enter the bloodstream via the lungs in order to be processed. Consequently, the heart is of central importance in both processes, breathing and the utilization of nutrients.

The muscle cells of the atrium also release ANP, atrial natriuretic peptide. Due to its vasodilatory activity (dilation of the blood vessels), atrial natriuretic peptide is mainly involved in the regulation or lowering of blood pressure, but also has an effect on the kidneys.

Diseases of the heart

Like all organs, the heart can be affected by specific diseases that impair its performance and endanger the health of the body. Heart disease is sometimes the result of congenital defects, but in many cases it is also a direct or indirect consequence of lifestyle. Factors such as diet, exercise, physical and mental stress and the consumption of intoxicants such as alcohol or nicotine have an effect on the condition of the heart and can cause diffuse clinical pictures.

The spectrum of different heart diseases is very broad. For this reason, the following sections only explain the most important or most common heart diseases.

Disorders and malfunctions

A well-known disorder of cardiac activity is cardiac arrhythmia. Here, the heartbeat follows an unusual frequency, which is divided into three types. High frequencies are called palpitations, low frequencies are called slow heartbeats. Extra beats (extrasystoles) can also occur. Cardiac arrhythmias are often caused by irregularities in cardiac conduction, but can also be due to a metabolic disorder (e.g. hyperthyroidism). Furthermore, arrhythmia is often a concomitant symptom of another heart disease (e.g. myocarditis).

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Some people suffer from congenital heart defects. These are usually caused by the anatomy of the heart. The incorrect formation of the organ during prenatal development manifests itself in adhesions, deformities and incorrect proportions. The distortion of the normal heart image is usually accompanied by reduced cardiac function.

Congenital heart defects at a glance:

  • Stenosis (narrowing) of the aortic arch or pulmonary valves
  • Atrial septal defect (opening in the septum between the atria)
  • Ventricular septal defect (opening in the septum between the ventricles)

High blood pressure, cardiac insufficiency, heart attack

Nowadays, high blood pressure is a widespread disease. Up to 50 percent of the European population is said to be affected. High blood pressure is characterized by the fact that the resistance in the blood vessels is higher than in a normal blood circulation. The heart has to pump harder to ensure a sufficient blood supply. With permanent hypertension (high blood pressure), the heart muscle gradually grows in size. However, the enlargement means that the muscle cells of the heart can no longer be supplied with a healthy amount of oxygen. The heart loses efficiency and is increasingly unable to withstand the pressure.

Alongside coronary heart disease, high blood pressure is therefore one of the most common causes of heart failure. Every year, 0.32 percent of the population suffers from heart failure. Doctors speak of heart failure when the heart is unable to pump a sufficient amount of blood through the body without an increase in pressure in the atria. In severe cases, a pacemaker is used. There is also the option of a heart transplant.

Doctors use the term coronary heart disease to refer to several clinical pictures that can lead to similar long-term consequences. These include

Myocardial infarction is the best-known heart disease. A heart attack is an acute emergency that leads to death in most cases if left untreated. If a coronary artery branch is blocked, the heart can no longer be fully supplied with blood, causing muscle cells to die. This in turn further restricts the heart's performance and causes a downward spiral of cardiac function.

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Other heart diseases:

  • Heart diseases of the valves (valve insufficiency and valve stenosis)
  • Pericarditis (pericardial disease as a result of an infection)
  • Functional cardiac neuroses (often not a typical case of heart disease; often of psychological origin)

Symptoms of heart disease

One of the first signs of heart disease is an irregular or unusual heartbeat (palpitations, extra beats or slowed heartbeats). Many patients also complain of tightness in the chest. Rapid exhaustion after minor exertion is a sign of cardiac insufficiency. This loss of performance is usually accompanied by increased tiredness and occasional cardiac arrhythmia.

Many heart diseases also manifest themselves in pain that radiates from the chest area to the back and left arm. Women in particular also suffer from diffuse upper abdominal pain. These symptoms are characteristic of a heart attack, but can also be caused by other heart diseases. Pain in the chest area must be clarified immediately with a doctor.

The symptoms of the various heart diseases are often similar. In order to determine the underlying cause and the best treatment, a doctor must examine your symptoms in more detail.

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