The heart is a hollow muscular organ

The heart is a hollow muscular organ located in the center of the chest. The right and left heart each has an upper chamber (atrium which collects blood and the lower chamber (ventricle) that draws blood. In order for blood to flow only in one direction, then the ventricle has a valve at the entrance and one valve on the way out. The main function of the heart is to supply oxygen to the body and cleanse the body from the metabolism (carbon dioxide). Heart perform these functions by collecting blood from a lack of oxygen throughout the body and pumps it to the lungs, where the blood picks up oxygen and dispose of carbon dioxide; heart then collects oxygen-rich blood from the lungs and pumps it to tissues throughout the body. CARDIAC FUNCTION At the time of pulsing, every heart chambers relax and fill with blood (called diastole), hereinafter the heart contracts and pumps blood out of the heart (called systole). Both atrium relaxes and contracts simultaneously, and both ventricles also loosens and contracts simultaneously. The blood that ran out of oxygen and contains a lot of carbon dioxide from the body flows through 2 venous encouraged (vena cava) leading to the right atrium. After the right atrium filled with blood, he will push blood into the right ventricle. The blood from the right ventricle to be pumped through the pulmonary valve into the pulmonary artery, to the lungs. Blood will flow through a very small vessels (capillaries) that surrounds the air pockets in the lungs, absorb oxygen and release carbon dioxide which then exhaled. Oxygen-rich blood flow in the pulmonary vein into the left atrium. Blood circulation between the right side of the heart, lungs, and the left atrium called the pulmonary circulation. Blood in the left atrium will be driven into the left ventricle, which then pumps the oxygen-rich blood through the aortic valve was entered into the aorta (the largest artery in the body). Oxygen-rich blood is supplied to the entire body, except the lungs. BLOOD VESSEL The entire circulatory system (cardiovascular system) consists of arteries, arterioles, capillaries, venules and veins. Arterial (strong and flexible) carry blood from the heart and bear the highest blood pressure. Flexibility helps maintain blood pressure between heart beats. Smaller arteries and arterioles have muscular walls that adjusts diameter to increase or decrease blood flow to certain areas. Capillaries are blood vessels smooth and very thin-walled, which serves as a bridge between the arteries (carry blood away from the heart) and veins (carry blood back to the heart). Capillaries allow oxygen and nutrients move from the blood into the tissues and allows the metabolism to move from the blood into the tissues. Of the capillaries, blood flows into the venules and then into the vein, which carries blood back to the heart. Veins have thin walls, but usually larger in diameter than arteries; thus veins carry blood in the same volume but with lower speed and less under pressure. BLOOD SUPPLY TO THE HEART Heart muscle (myocardium) itself receives a portion of a volume of blood flowing through the atria and ventricles A system of arterial and venous (coronary circulation) supply oxygen-rich blood to the myocardium and then returns the oxygenated blood to the right atrium. Right coronary artery and the left coronary artery is a branch of the aorta; cardiac veins drain blood into sinurskoroner, which returns blood to the right atrium. Most of the blood flow into the coronary circulation during moderate heart relaxes between pulse (during ventricular diastole).