The heart is a hollow muscular organ in the body of animals, the main function of which is the circulation of fluid in the body. It is located in the middle of the chest. The human heart has a mass of 200-425 grams. The heart is built of cardiac muscle tissue. It is well covered, which provides enough food and oxygen. Blood supplies the body with oxygen and nutrients, and is also involved in the removal of metabolic waste. In humans, the heart is located between the lungs, in the central part of the chest.
The heart is divided by a muscular wall on the left and right sides. Each side is divided into two parts - a smaller atrium and a larger chamber. It is commonly believed that the right ankle and camera are called the "right heart", and their left cord is called the "left heart". In contrast, fish have two chambers, an entrance hall and a chamber, while reptiles have three chambers. Heart valves regulate the flow of blood from the atrium to the chamber. They act as valves: they allow blood to flow in one direction from the atrium to the chamber. The blood flow that passes from the atrium into the chamber closes the valves of the heart, and blood return is impossible. The heart is enclosed in a protective shell, the pericardium, which also contains a small amount of fluid. The heart wall consists of three layers: pericardium, myocardium and endocardium.
The heart pumps blood with a rhythm determined by a group of rhythmic cells in the sinoatrial node. They generate a current that causes the heart to contract, passing through the atrioventricular node and the conductive cardiac system. The heart receives low-oxygen blood from the systemic circulation, which enters the right atrium from the upper and lower large veins of the vein and passes into the right chamber. From there, the blood is pumped into the pulmonary circulation through the lungs, where it receives oxygen and releases carbon dioxide. The oxygenated blood then returns to the left atrium, switches to the left ventricle, and is pumped through the aorta into the systemic circulation - where oxygen is used and metabolized to carbon dioxide. The heart rate is about 72 beats per minute when the body is resting. During physical activity, the temporary heart rate accelerates, but over time, the frequency returns to the resting level.
According to 2008 data, cardiovascular diseases are the most common global cause of death. They cause about 30% of deaths. Of which , more than three quarters are the result of coronary heart disease and stroke . Risk factors include: smoking, overweight, insufficient physical activity, high cholesterol, high blood pressure and poorly controlled diabetes, among others. Cardiovascular diseases often have no symptoms or can cause chest pain or shortness of breath. Diagnosis of heart disease is often performed based on medical history, listening to heart tones using a stethoscope, ECG and ultrasound analysis. Specialists specializing in heart diseases are called cardiologists, although many other medical specialties are also involved in the treatment. 1xbet প্রোমো কোড নিবন্ধন
