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.