Question

Give an account of working of the human heart.

Answer 1

• The human heart is made up of four chambers. The upper two chambers are called the atria and lower two chambers are called ventricles.
  
• Deoxygenated blood is received by the heart from the body through superior and inferior vena cava. The superior vena-cava carries deoxygenated blood from the upper region and inferior vena cava(which is larger than the superior one) from the lower region of the body.
  
• The blood from both the vena-cava is received by the right atrium. Right atrium also receives blood from coronary sinuses(vessels of the heart itself). This blood (deoxygenated) flows into the right ventricle.
• The opening between the right auricle and ventricle is guarded by a bicuspid valve called the mitral valve. Now blood from right ventricle is pumped into the lungs(for oxygenation) through the pulmonary artery.
  
• After the blood is oxygenated in the lungs, it is again received by the heart.in the left atrium through the pulmonary vein. Now the blood from left atrium flows into the left ventricle. The opening of the left atrium and ventricle is guarded by the tricuspid valve.
  
• The left ventricle is now containing the oxygenated blood which is pumped through the aorta and reaches all the organs through arteries.