Heart

• Double Circulatory System

  The human heart system is described as double circulatory because is has two separate circuits. The first carries blood between the heart and the lungs and is known as the pulmonary circuit and the second carries blood between the heart and the other organs and is known as the systematic circuit
• Blood flow through the heart

  1. Deoxygenated blood from body enters the veins

  2. Flows to the right atrium

  3. Valve between the right atrium and ventricle prevents backflow

  4. Blood flows to the right ventricle

  5. Blood flows out of the pulmonary artery

  6. Blood goes to lungs

  7. Oxygen diffuses into blood through alveoli

  8. Oxygenated blood flows back into the pulmonary vein

  9. Flows to the left ventricle

  10. Valve between the left atrium and ventricle prevents backflow

  11. Blood flows to the right ventricle

  12. Blood flows out the aorta

  13. Delivered to all parts of the body that need it
• Why is left side of heart thicker?

  Pumps blood at a much greater distance around the body