The heart

• Circulatory System

  Made up of heart, blood vessels, and blood
• Circulatory System in humans


  1. Right ventricle pumps deoxygenated blood to the lungs

  2. Blood returns to heart

  3. Left ventricle pumps oxygenated blood around the body

  4. Body gives up oxygen to blood cells

  5. Deoxygenated blood returns to heart
• Heart

  • A pumping organ
  • Walls mostly made of muscle tissue
  • Has valves to ensure blood goes in the right direction
• Heart chambers

  • Left ventricle
  • left atrium
  • Right atrium
  • Right ventricle
• Blood flow through the heart

  1. Blood flows into atria from vena cava and pulmonary vein

  2. Atria contract, pushing blood into ventricles

  3. Ventricles contract, forcing blood into pulmonary artery and aorta

  4. Blood goes to organs through arteries and returns through veins

  5. Atria fill again, repeating the cycle
• Coronary arteries


  Arteries that branch off the aorta and surround the heart, supplying it with oxygenated blood
• Heart pacemaker


  • Group of cells in the right atrium that produce small electric impulses which spread to the surrounding muscles, causing them to contract
• The resting heart rate is controlled by the heart's pacemaker