The heart is a hollow muscle organ, where without mixing blood, a large (systemic) circle of blood circulation with a small pulmonary intersects. For this reason, it is called the central organ of the cardiovascular system. Blood flows through the hollow veins to its right sections, which, after getting into the right ventricle, leads the pulmonary trunk to the lungs. From them, blood is diverted to the left atrium by means of 4 pulmonary veins, and from the ventricle to the periphery it is sent by the aorta.
Cardiac anatomy
The heart is a hollow organ, the bulk of which is the myocardium, consisting of myocytes and pacemakers. The heart muscle forms a “bag” with four cavities: two atria and two ventricles. The right atrial cavity receives venous blood from the systemic circulation and directs it through the atrioventricular outflow tract to the ventricle. Its wall is thin, only about 3-4 mm, and the pressure in the cavity is much lower than in the left ventricle (LV).
The atria of the heart are filled with blood at the time of the ventricular diastole, and then the blood itself enters the ventricles, although at the end of diastolic filling there is still a slight atrial systole. After a split second, into the ventricular systole, this blood will be directed to the pulmonary trunk and the aorta.
Valve apparatus
To prevent the backflow of blood into the atrial cavities and its delay in the ventricles, a valvular apparatus is developed in the heart. Heart valves are derivatives of connective tissue that block intracardiac regurgitation. The cavity of the right atrium and ventricle closes the tricuspid (right AB-) valve. A reverse flow of blood into the cavity of the right ventricle prevents the tricuspid valve of the pulmonary trunk.
At the anatomical border of the left atrium and ventricle is the mitral valve, which consists of only two cusps. Blood is carried out from the LV through the aortic tract to the aorta, the largest artery of the body, capable of withstanding high hydrostatic pressure and transmitting a pulse wave. A massive aortic valve is located on this site .
Heart abduction vessels
The aorta and pulmonary trunk are arterial vessels that divert blood from the heart. Oxygenated blood enters the systemic peripheral blood flow through the aorta, and into the lungs through the pulmonary trunk to the place where the venous blood is saturated with oxygen. The pulmonary trunk is the only adult artery through which venous blood flows containing a small amount of oxygen.
Conversely, 4 pulmonary veins that flow into the left atrium are the only venous vessels in the adult body that carry oxygenated arterial blood. In a healthy person, venous and arterial blood does not mix, as they fill different cavities of the heart.
Pulmonary trunk
This blood vessel is the beginning of the pulmonary circulation. The pulmonary trunk delivers venous blood to the lungs under low hydrostatic pressure from the right ventricle. Its diameter reaches 3 cm. The valve of the pulmonary trunk consists of 3 valves at the mouth, from where the vessel goes up and to the left, in front of the aorta. Then it goes around the aortic vessel on the left and at the level of 4 thoracic vertebra is divided into 2 short pulmonary arteries.
The right pulmonary artery (LA), heading to the corresponding lung, is located behind the ascending aorta and the vena cava. The left aircraft goes ahead of the descending aorta. At the gates of the lungs, they are divided into lobar branches, and then into small arteries, arterioles, precapillaries and capillaries. With their help, venous blood is delivered to the airborne barrier at the level of the smallest vessels where oxygenation will occur.