The circulatory system allows the proper functioning of blood circulation. It consists of a pump, the heart, and a series of pipes that take the name of the blood vessels.
The heart is placed in the rib cage in a space between the two lungs called the mediastinum.
It is as big as a fist and weighs about 300 grams. It is divided into four sections, two upper, called atria and two lower, called ventricles.
The right atrium and the left are separated from each other by the interatrial septum, while the two ventricles are separated by the interventricular septum. The right atrium communicates with the right ventricle through a valve called the tricuspid, while the left atrium communicates with the left ventricle through a valve called bicuspid or mitral. At the level of the right atrium there is the mouth of the superior and inferior quarry vein, while in the left atrium there is the mouth of the pulmonary vein.
At the level of the right ventricle is located the pulmonary artery, while at the level of the left ventricle is located the aorta artery, which is the most important vein in the body.
The circulatory system caters both large circulation that the small circulation. The large circulation originates from the left ventricle through the aorta and carries blood to the tissues.
At the level of arterial capillaries the blood gives off oxygen and nutrients, immediately after at the level of the venous capillaries the blood collects waste substances and carbon dioxide. By venous capillaries originates the venous network that ends with the superior quarry veins and the inferior quarry veins which shed blood in the right atrium.
The small circulation has the purpose to bring the blood to the lungs so that it can give in carbon dioxide and charging of oxygen. It originates from the right ventricle through the pulmonary artery and ends with the pulmonary veins that carry blood into the left atrium.
The heart in its functioning produces two sounds called heart sounds, which can be heard through a tool called a stethoscope.
The first tone is due to the closure of the atrioventricular valves with the passage of blood from the atriums to the ventricles; the second tone is due to the closure of the semilunar valves with the passage of blood from the ventricles to the large arteries.
The normal values of cardiac pressure are about 70 per minute.
The normal values of cardiac pressure are between 120 (maximum systolic pressure) and 80 (minimum diastolic pressure). The pressure is measured by the sphygmomanometer.