Kerala PSC - Biology - Human Body (Heart)

• 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.