Animation: how your heart pumps

See how the heart works with this animated diagram.

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For instructional purposes, this animation shows blood flow through the right and left hand sides of the heart separately. In reality, the 2 sides of the heart perform their functions at the same time and blood is flowing through both sides of the heart at the same time.

Your heart is divided into 4 chambers: 2 on the right hand side and 2 on the left. Each upper chamber is known as an atrium and each lower chamber as a ventricle. Blood comes into the heart via the atria and is pumped out via the ventricles.

The right side of the heart

The right side of the heart pumps blood needing oxygen to the lungs.

  • Venous blood from the body that is in need of oxygen enters the right atrium of the heart via 2 large veins — the vena cavae. Blood from the upper body enters via the superior vena cava, and blood from the lower body enters via the inferior vena cava.
  • The blood flows from the right atrium into the right ventricle.
  • The right ventricle squeezes and pumps the venous blood to the lungs via the pulmonary arteries.
  • In the lungs, the blood picks up oxygen, and carbon dioxide is removed.

The left side of the heart

The left side of the heart pumps oxygen-rich blood from the lungs to the rest of the body.

  • Oxygen-rich blood from the lungs enters the left atrium of the heart.
  • Blood is pumped from the left atrium into the left ventricle.
  • The left ventricle contracts and pumps the oxygen-rich (arterial) blood to the body via the aorta.


1. National Heart Foundation of Australia [website]. Your heart and how it works information sheet (published 2008. Available at: (accessed 2010, Feb 22)
2. National Heart, Lung and Blood Institute [website]. How the heart works (revised 2009, July). Available at: (accessed 2010, Feb 22)