MAIN FUNCTIONS OF THE HEART The role of the heart is to pump oxygen-rich blood to every living cell in the body. In order to achieve its goal, it must continuously beat for a person’s entire lifespan. Because of its vital role, a non-beating heart always results in death
The heart beats almost like a clock, about 60 to 80 times per minute, CONTINUOUSLY, whether you are asleep or awake. The heartbeat is regulated by a small "battery" located in the right atrium called the SINUS NODE. Electric currents travel in the heart by means of minute fibers in the wall of the heart, much like concealed wiring inside a room.
THE HEARTBEATThe heartbeat is made up of systole and diastole, which are the two stages of a heartbeat.
SYSTOLE Stage when the ventricles of heart are contracting resulting in blood being pumped out to the lungs and the rest of the body. Thick, muscular walls of both ventricles contract. Pressure rises in both ventricles, causing the bicuspid and tricuspid valves to close. Therefore, blood is forced up the aorta and the pulmonary artery. The atria relax during this time. The left atrium receives blood from the pulmonary vein, and the right atrium from the vena cava.
DIASTOLE Stage when the ventricles of the heart are relaxed and not contracting. During this stage, the atria are filled with blood and pump blood into the ventricles. Thick, muscular walls of both ventricles relax. Pressure in both ventricles falls low enough for bicuspid valves to open. The atria contract, and blood is forced into the ventricles, expanding them. The blood pressure in the aorta is decreased, therefore the semi-lunar valves close.