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explain the process of heart? |
The purpose of our heart is to pump fresh blood to the organs and tissues of our body that need the oxygen and nutrients it carries. The oxygen-rich blood is pumped out of the left side of our heart into the arteries to these tissues and organs. How heart works The heart is made up of 2 pumps. The pump on the right hand side receives blood that has already delivered its oxygen round the body and sends this blood to the lungs to pick up more oxygen ( to get rid of carbon dioxide). The pump on the left hand side receives oxygen-rich blood and then pumps it out into the arteries to deliver its oxygen around the body. Blood in need of oxygen Blood in need of oxygen from around the body comes in the veins to the heart. This blood in need of oxygen (also called deoxygenated blood) is usually shown as blue or purple on diagrams. This ‘deoxygenated’ blood enters the top right hand side chamber of the heart, which is called the right atrium, via two large veins. Blood from the upper body, e.g. the head and arms, comes in via the superior vena cava. Blood from the lower body, that is the trunk and legs, comes in via the inferior vena cava. Blood passes from right atrium to right ventricle. When the right atrium fills, the blood then passes through a one-way door (valve) called the tricuspid valve into the right ventricle. The valve stops blood from flowing backwards into the right atrium once it’s in the right ventricle. The right ventricle relaxes and venous blood in need of oxygen flows in. Right ventricle sends blood needing oxygen to the lungs. The blood needing oxygen is pumped out of the right ventricle, through the pulmonary valve into the pulmonary artery. The pulmonary artery then divides into the right and left pulmonary arteries, carrying blood to the right and left lungs. In the lungs the blood gives up its carbon dioxide and picks up oxygen. Oxygen-rich blood from lungs enters heart. Fresh blood full of oxygen leaves the lungs and comes back to the heart in the pulmonary veins. This oxygen-rich blood enters the left atrium — the top left chamber of the heart. Blood passes from left atrium to left ventricle. When the left atrium is full it pushes the blood through the mitral valve into the left ventricle. Left ventricle sends oxygen-rich blood around body. The left ventricle relaxes and fills up with blood before squeezing and pumping the oxygen-rich blood through the aortic valve into the aorta — the main artery that carries blood to your body. The muscle wall of the left ventricle is very thick because it has to pump blood around the whole body. It is then forced into the aorta and the process repeats. |