Why the heart beats
In ancient times, the Greeks believed that the heart - is the seat of the spirit, the Chinese believed that there lived happiness, the Egyptians believed that it originate intellect and emotions. How does it work this unique authority responsible for the whole body?
The heart consists of four sections or chambers. At the top of the atrium located: right and left, and at the bottom - the ventricles, and left and right. Thus they do not communicate with each other. On the surface of the heart is full of branching fibers that generate and transmit electrical impulses. These pulses, or as they are called "signals", Arise on the surface of the sinus node of the right atrium. From there the impulse passes through the atrium, it reduces and goes down the ventricle, and simultaneously reducing stomach muscle fibers. Thus, the reduction time occurs volnoobrazno.Vo contraction of cardiac muscles of the right atrium and venous blood is ejected is directed to the right ventricle, which in turn pushes it to the pulmonary circulation - in pulmonary vascular network. There, the carbon dioxide released from the blood, and the blood oxygen supplied from the air, that is gas exchange occurs. Thereafter, oxygenated blood enters the left atrium, and from there - to the left ventricle. Then it is pushed through the aorta to the systemic circulation throughout the body. So during heart muscle relaxation in the body enters a new portion of the blood. With this electrical system heart "beats" and there is an exchange of blood. In one blow heart pumps about 100 cubic centimeters of blood, that is 10,000 liters per day. On the day for approximately 100,000 heartbeats and the same it is resting between beats. In general, during the day the heart is resting 6 hours. The normal frequency of contractions in a healthy person at rest about 60-80 per minute.