Heart(ഹൃദയം)part 2 скачать в хорошем качестве

Heart(ഹൃദയം)part 2

The heart is situated in the thoracic chamber between the two lungs. Heart is a vital organ of the body whose normal function is to contract periodically in order to pump either haemolymph or blood to various parts of the body. The human heart is divided in four chambers The upper chambers are called auricles and the lower chambers are called ventricles. Heart is protected by a double layered membranous sac called pericardium. The heart begins to beat at the age of 4 weeks of the embryonic stage. Heart contracts about 72 times a minute in an adult. The contraction phase is called systole and relaxation phase, a diastole. Heart beat of a foetus  is more than 200 per minute. It will reach 140 per minute at the time of delivery. The accumulation of cholesterol in the arteries is known as arteriosclerosis. In Bypass Surgery the blocked blood vessel is replaced by another blood vessel. Block in the blood vessel is removed by using new medical equipment known as angioplasty. Blood clotting that occurs in the blood vessels of brain is known as 'Cerebral thrombosis'. Hemorrhage occurs when the pressure increases in the walls of arteries so that they become broken. Stroke is the condition in which the flow of blood is decreased in the areas of brain, so that fatigue occurs. Weight of human heart is 300 g. The organ which cannot affect the cancer is the heart. First artificial heart is Jarvick 7. ECG (Electrocardiograph) is used to known the disorders of heart. This technique was first developed by William Einthoven in 1903. High blood pressure is known as the silent killer. Human RBC contains no nucleus. But in camel, the RBC contains nucleus. The only artery which carries deoxygenated (Impure) blood - Pulmonary artery It carries blood from right ventricle to lungs. The only vein which carried oxygenated (Pure) blood from lungs to left auricle - Pulmonary vein. The fine branches of the arteries and veins are connected together by extremely fine vessels called capillaries. In an average healthy man, the systolic pressure is about 120mm/Hg and the diastolic pressure is about 80 mm/Hg. Increase rate of Heart beat - Tachycardia Decreased rate of Heart beat - Bradycardia High levels of Potassium and Sodium ions decrease the heart rate.