How the hearth works? Essay

pericardium. Made up of connective tissue and fats, its function is to act as an additional layer of protection underneath the pericardium. The myocardium is made up of fibres of cardiac muscle tissue, its function is to contract and relax, pushing blood around the hearts chambers. The endocardium is a smooth layer made up of endothelial tissue which lines the chambers of the heart. Its smooth surface allows blood to flow with ease (Kabra, 2013).
The internal cavity of the heart consists of four chambers, the right atrium, right ventricle, left atrium and the left ventricle. The upper chambers of the heart, the left and right atrium, act as a receiving chamber and contract to push blood into the lower chambers, the left and right ventricle. The left ventricle pumps blood to the rest of the body and the right ventricle pumps blood to the lungs. The right side of the heart (right atrium and right ventricle) involves pulmonary circulation, whereas the left side (left atrium and left ventricle), involves systemic circulation. During pulmonary circulation, oxygen depleted blood is received from the body through the right atrium, this travels through to the right ventricle and then goes into the pulmonary arteries before entering the right lung where carbon dioxide is released and the blood is replenished with oxygen. The oxygenated blood re-enters the heart ready for systemic circulation into the left atrium and then goes through to the left ventricle from which it is pumped around the body (Bittihn, 2015).
As blood passes from one chamber of the heart to another, it passes through a valve these valves are made up of connective tissue. The function of the valves are to act as gates to ensure a coordinated one way blood flow around the heart, preventing a backward flow. The heart has four valves, the tricuspid valve, pulmonary valve, mitral valve and aortic valve. The mitral and tricuspid valves separate the atria from the ventricles. The aortic and pulmonary valves separate the ventricles from the arteries. The tricuspid valve is located between the right atrium and right ventricle and the pulmonary valve is located between the right ventricle and pulmonary artery. The mitral valve is located between the left atrium and left ventricle, whilst the aortic valve is located between the left ventricle and the aorta.
Without blood vessels, the heart would be unable to function. Blood vessels provide a pathway for blood pumped by the heart to travel around the body. Arteries carry oxygenated blood away from the heart at high pressure, except for the pulmonary artery, which carries de-oxygenated blood to the lungs. The largest artery is the aorta, situated at the top of the left ventricle, the aorta branches into several arteries which through which blood travels to different parts of the body. Veins carry de-oxygenated blood to the heart at a low pressure, except for the pulmonary vein which carries oxygenated blood from the lungs to the heart. The two largest veins in the body are the superior and