- Heart position
- Heart functions
- Basic structure of the heart
- The heart's conductive system
- Heart rate and blood pressure
- Heart disease
- Diagnosis of heart disease
- What is the most harmful to our heart?
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The heart is one of the most important organs of our body. It acts as a central pump that supplies blood to the rest of the body. His constant, painstaking work ensures the smooth functioning of all tissues, supplying them with oxygen and draining waste products. How does our heart work and how can we help it?
The heart , unlike the muscles that are subject to the will of our will, cannot rest even for a moment. It contracts an average of 72 times a minute, and has to pump around 173 million liters of blood over the course of its life. Many of our activities, such as a poor diet or a sedentary lifestyle, can sabotage the proper functioning of the heart and lead to serious diseases.
The human heart is located in the central part of the chest, also known as the mediastinum. Most of the heart, about 2/3 of the organ, is on the left side of the body with its long axis leading to the right arm. This organ is located directly between the lungs, therefore the physiologically human left lung has a smaller area than the right one.
The popular and eagerly drawn heart symbol has little to do with the actual shape of this organ, rather resembling a slightly irregular, inverted cone.
The size of an adult's heart is often compared to the size of a fist, but in trained athletes who regulate their aerobic effort, it can be much larger.
The heart is surrounded by a special membrane bag - the so-called pericardium - filled with fluid inside. Thanks to this structure, the friction between the constantly moving heart and other adjacent organs is minimized.
The main task of the heart is to pump blood to two circuits: the main and the pulmonary. In the main circuit (i.e. large or systemic), through the blood, the heart supplies tissues with oxygen and substances necessary for proper metabolism.
At the same time, it collects de-oxygenated, dark red venous blood, supporting the removal of metabolic products.
In the pulmonary circulation, the heart enables blood to be supplied to the lungs for oxygenation and removal of carbon dioxide. The uninterrupted, regular work of the heart as a pump is guaranteed by the double-track and simultaneous transportsubstances in the body.
Basic structure of the heart
The human heart is nothing more than a very efficient muscle, made of specializedstriated muscle tissue . This type of tissue is found only in the heart of vertebrates. It is one of the very few muscles in our body that cannot work at will.
The heart consists of two atria and two chambers. Thanks to the symmetrical structure, they can be divided into 2 sides:
Two main veins enter the right atrium, supplying the deoxygenated (or "used" for metabolic processes) venous blood:
- superior vena cava (containing venous blood from the upper body, including the head, shoulders, and chest)
- inferior vena cava (supplying blood e.g. from the abdominal cavity or legs).
Venous blood from the coronary circulation (supplying blood to the walls of the heart) also flows into the right atrium.
The right atrium is separated from the right ventricle by a valve (tricuspid). Valves are special membranes that prevent the uncontrolled regurgitation of blood during heart contractions.
ExactlyThanks to the correct operation of the valves, a he althy heart pumps blood in only one direction .
Venous blood enters the right ventricle through the open valve. It is a cavernous space with rather thin walls, the structure of which is strengthened by the so-called muscular trabeculae. The right ventricle ends with the so-called the pulmonary trunk, to which blood is pumped when it contracts.
The pulmonary trunk, separated by the valve, divides into the right and left arteries, supplying blood to both lungs. After gas exchange in the alveoli (oxygen and carbon dioxide), oxygenated blood is collected through small capillaries and then through larger veins. It then flows through the four pulmonary veins to the left atrium of the heart.
Blood circulation in the pulmonary circulation is a separate and closed element in the circulatory system, which is why it is often called the so-calledsmall blood circulation .
The left ventricle of the heart is responsible for pumping blood around the body. This is the peripheral circulation, also calledbig blood circulation . Unlike the right ventricle, the left ventricle has to do much more work when "pushing out" the fluid, which is why its walls are thicker.
Blood enters the aorta through the aortic valve - the largest artery in the human body, through which it is distributed to all tissues.
Anatomical structure of the human heartSee the gallery of 5 photos
The heart's conductive system
Rhythmic contractions and contractions of the heart and its regular work would not be possible if it were not for the electrical impulses and regular stimulation of the muscle, maintained by the so-called the heart's conductive system. It consists of:
- sinoatrial node,
- atrioventricular node,
- a bunch of Hisa,
- Purkinje fibers.
The sinoatrial node, also known as the "pacemaker", has the ability to spontaneously generate electrical excitations. Its work can be compared to a machine that determines the heart rate.
Pulses propagate further to other structures of the heart through the atrioventricular node, which slows down the conduction of impulses and prevents simultaneous contraction of the ventricles and atria. His bundles and Purkinje fibers branch the network through the septum of the heart and deliver the pulses eventually to the ventricular fibers.
Efficient work of the heart's conductive system ensures the correct rhythm of the heart muscle and the subsequent contraction of the atria and ventricles. To check if this system is working properly, an electrocardiographic (EKG) test is performed, analyzing the electrical activity of the heart.
Heart rate and blood pressure
The working heart, through regular ejection of blood from the ventricles, forces the pulsating movement of the artery walls, calledpulse or pulse . It is one of the parameters that can be used to easily assess the heart rate and the elasticity of blood vessels.
The heart rate can be checked with a camera or by touch (palpation) on the arteries close to the skin surface, most often the artery:
During diagnostics, its frequency, amplitude and regularity are also assessed, as well as the duration of the systolic wave or the presence of murmurs over the arteries.
Normal resting heart rate for an adult is approximately 70 beats per minute . These values increase, especially after drinking alcohol, coffee, in stressful situations or after exercise.
Pulse values that are too high, in the range of 180-200 beats per minute, indicate sinus tachycardia , requiring in-depth diagnosis.
The second parameter, key to assessing the condition of the cardiovascular system, isblood pressure . It is the pressure that flowing blood exerts against the walls of blood vessels. The pressure values depend on many factors, including:
- force of contraction of the heart muscle,
- diameter and degree of filling of blood vessels,
- age of the patient,
- and even from the time of day.
Blood pressure is characterized by two values:
- systolic blood pressure
- diastolic pressure.
The first value is the maximum pressure the blood reaches during the contraction of the heart, pumping it throughout the body. Diastolic pressure is when the heart is in its diastolic phase and represents the minimum blood pressure level between heart beats.
Normal blood pressure values should be between 120 and 129 (systolic) and 80 and 84 (diastolic).
Blood pressure values may increase with age, howeverrepeated readings above 140/90 mmHg indicate hypertensionthat requires treatment.
The heart is exposed to many negative factors throughout its life, which makes it prone to various diseases. For many years, cardiovascular diseases have been the leading cause of death in Poland, much more dangerous than cancer.
It is estimated that as many asabout 46% of deaths in recent years in our country occurred due to cardiological diseases.Compared to other European countries, these statistics are terrifying.
The most common diseases and conditions that directly affect the heart include:
Coronary artery disease
Coronary artery disease - otherwise ischemic heart disease - a chronic condition caused by hypoxia of the heart muscle cells, leading to its failure. It is mainly caused by:
- atherosclerosis (an insidious disease consisting of the deposition of excess cholesterol and other lipids in the walls of the arteries),
- less often due to congestion, narrowing or underdevelopment of coronary arteries,
- some injuries
- or after carbon monoxide poisoning.
Coronary artery disease is also called angina , because its symptom is severe pain and shortness of breath around the chest during exercise. Pain can radiate (most often left) to the arms, hands and even the jaw.
Myocardial infarction - also colloquially known as a heart attack - is a necrosis of the heart muscle caused by its ischemia. It is caused by the closure of the coronary vessel that carries blood to the heart.
Previous coronary artery disease and atherosclerosis are responsible for a heart attack in over 90% of cases.
Myocardial infarctions are usually sudden, violent,manifested by severe pain in the retrosternal area . Patients complain tooto:
- feeling short of breath,
- spreading the chest,
- and vomiting.
A heart attack is a very serious disease with a high mortality rate, often resulting in many complications and can permanently damage the heart as a pump.
Heart attacks are diagnosed in ever younger people, mainly men under 45, burdened with stress and an unhe althy lifestyle.
Disturbances in heart rhythm - the so-called cardiac arrhythmias - this is a large group of disorders that can be divided into 2 types:
- supraventricular arrhythmias (such as atrial fibrillation, atrial, nodal, or atrioventricular tachycardia)
- and ventricular arrhythmias.
Supraventricular disorders are usually found in people without additional heart disease and may be a risk factor for future cardiovascular disease (e.g. stroke).
Ventricular arrhythmias (including additional ventricular contractions, ventricular fibrillation, ventricular tachycardia) - in turn, these are very serious diseases, usually associated with the need to call an ambulance and treatment in a hospital.
There can be many causes of arrhythmias, ranging from complications of ischemic heart disease, through acquired and congenital heart defects, genetically determined diseases of the conductive system, or arterial hypertension.
Arrhythmias can manifest themselves, for example:
- palpitations and tachycardia (i.e. too fast heart rate),
- feeling short of breath,
Myocarditis - unlike the previously mentioned diseases - this disease arises as a complication of past infections:
- viral (e.g. influenza, chickenpox or rubella)
- or bacterial (staphylococcal, salmonella or pneumococcal infections).
In young people, this inflammation may also have an autoimmune background.
The ailments accompanying this disease are:
- quick fatigue during any physical activity,
- shortness of breath,
Untreated heart inflammation can lead to the replacement of normal cells with fibrosis, which leads to a significantly reduced heart muscle performance.
Valve defects - are a congenital or acquired disease (e.g. after severe infections). The most common types of valve disease include
- valve stenosis - whennarrowed outlet of blood makes it difficult to pump it properly,
- and valve regurgitation - which causes blood to "leak" and regurgitate.
As a result of defects in the valves, the heart works harder and harder and the disease worsens. Symptoms may include:
- shortness of breath,
- chest pain,
- or swelling around the ankles and feet.
Diagnosis of heart disease
The tests performed in the first place in the case of suspected heart diseases are non-invasive tests that will help to exclude other causes of ailments in the presence of non-specific symptoms in the patient.
These are the most common:
- Blood tests - apart from the standard blood count, the so-called specific heart markers, i.e. enzymes whose concentration increases due to hypoxia and damage to the heart muscle cells. The most popular markers are troponins (cTn) and creatine kinase (CK) or B-type natriuretic peptide (BNP). However, such results should be analyzed very carefully, because, for example, an increased concentration of troponins occurs after strenuous exercise - like running a marathon - and then does not mean a pathological condition.
- Magnetic resonance imaging (NMR) - currently one of the most accurate and popular methods of in-depth non-invasive diagnostics in cardiology. It allows you to visualize the processes taking place in the heart, and thanks to the high resolution of the image, it also allows for the differentiation of tissues and assessment of their functions.
- Echocardiography - this is an ultrasound test that allows you to assess the internal structure of the heart and possible abnormalities.
- Electrocardiogram - it can be used to measure the bioelectric activity of the heart. It is safe and cheap, and it can be used to detect, for example, chronic disorders of the heart blood supply, arrhythmias and even the so-called "Silent" myocardial infarction (previous asymptomatic infarction that leaves a permanent mark on the heart muscle).
Coronary angiography is an invasive test used in cardiology, requiring a hospital stay. In this technique, a contrast agent is introduced into the patient's body through one of the arteries, which allows the network of coronary vessels to be visualized in the X-ray image.
What is the most harmful to our heart?
Unfortunately, we have no influence on a number of elements that may be a potential factor in the development of cardiovascular diseases. They are, for example:
- age (men>55, women>60),
- male gender,
- a family history of heart disease or high blood pressure.
In developed societies, however, heart disease affects younger and younger individuals. It turns out that our he alth is strongly influenced primarily by our lifestyle. Increasingly longer hours of sitting, computer and TV entertainment, and processed diets are the main culprits behind such high rates of cardiovascular disease.
Doctors currently list a few of the most important risk factors for cardiological diseases:
- overweight and abdominal obesity
- little physical activity
- high cholesterol
- alcohol abuse
Experts indicate that about 150 minutes of moderate-intensity aerobic physical activity (e.g. walking or walking) a week will greatly improve our condition and heart function.
Combined with a less fat diet and quitting smoking, regular exercise will surely be a ticket to he alth and the best friend of our heart. Following the principle that prevention is better than cure, let's take care of heart prophylaxis and enjoy a long life.