The heart

• The heart is an organ that pumps blood around the body.
• Cells in the heart are supplied with oxygenated blood by the coronary arteries.
• 1. pulmonary artery
  2. vena cava
  3. right atrium
  4. right ventricle
  5. aorta
  6. pulmonary vein
  7. left atrium
  8. left ventricle

  
• Pulmonary artery carries deoxygenated blood from heart to lungs.
• Aorta carries oxygenated blood from heart to the body
• Vena cava brings deoxygenated blood from the body to the heart.
• Pulmonary vein brings oxygenated blood from the lungs to the heart
• Valves precent blood flowing the wrong way through the heart ( backflow )
• Left ventricles muscle wall is thicker than the right ventricle as it pushes blood all round the body
• 1. Blood enters the atria
  2. The atria contracts forcing blood into the ventricles
  3. The ventricles contract forcing the blood into the arteries
  4. Blood flows through arteries to the organs and returns to the heart through the veins.
• Humans have a double circulatory system . The right ventricle pumps blood to the lungs where gas exchange takes place . The left ventricle pumps blood around the rest of the body