Heart and Blood Vessels

• Blood Vessels

  Arteries carry oxygenated blood away from the heart (except the pulmonary artery)

  Veins carry deoxygenated blood towards the heart (except the pulmonary vein)

  Capillaries exchange substances
• Blood Vessels

  • Arteries
  • Veins
  • Capillaries
• Veins


  • Carry deoxygenated blood to the lungs (except the pulmonary vein)
  • Large lumen (minimizes resistance to flow)
  • Thinner layer of muscle and elastic fibers
  • Valves (to prevent backflow)
• Capillaries


  • Very small (to fit between cells)
  • Narrow lumen
  • Thin endothelium - one cell thick (to maintain short diffusion distance and fit between cells)
• Arteries

  • Carry oxygenated blood to the body tissues (other than the pulmonary artery)
  • Have a small lumen to maintain high blood pressure
  • Smooth inner endothelial lining (a smooth surface means there’s less resistance to blood flow)
  • Thick layer of smooth muscle (contract and relax to dilate and constrict blood vessels - controlling their diameter) and elastic fibers (stretch and recoil)
  • Lots of collagen fibers (for strength and support)
• Atrium


  A chamber in the heart which receives blood directly from a vein and passes it on to a ventricle
• Artery


  A type of blood vessel that carries blood at high pressure away from the heart
• Left atrium


  The chamber in the heart that receives oxygenated blood from the pulmonary vein and passes it on to the left ventricle
• Pulmonary artery


  The main artery that carries deoxygenated blood from the heart to the lungs for reoxygenation
• Aorta


  The main artery that carries oxygenated blood away from the heart at high pressure
• Ventricle


  A chamber in the heart which receives blood from the atrium above it and pumps it out of the heart
• Right atrium


  The chamber in the heart that receives deoxygenated blood directly from the vena cava and passes it on to the right ventricle
• Vein


  A type of blood vessel that carries blood at lower pressure into the heart from other parts of the body
• Venule


  A smaller type of blood vessel that connects capillaries with veins
• Arteriole


  A smaller type of blood vessel that connects arteries with capillaries
• Capillary


  A very small blood vessel with thin walls and a small diameter used for substance exchange in tissues
• Coronary artery


  The main artery that supplies the heart tissue with oxygenated blood
• Left ventricle

  The chamber in the heart that receives oxygenated blood from the left atrium and pumps it out of the heart to the rest of the body
• Pulmonary vein

  The main vein that carries oxygenated blood away from the lungs and back to the heart
• Right ventricle


  The chamber in the heart that receives deoxygenated blood from the right atrium and pumps it out of the heart to the lungs for reoxygenation
• Vena cava


  The main vein that carries deoxygenated blood into the right atrium of the heart
• Atrioventricular valves


  Between the atria and the ventricles

  Prevent blood flowing back into the atria when the ventricles contract
• What is the purpose of the atrioventricular valves?


  To stop blood flowing back to the atria
• Semi-Lunar Valves


  Between the ventricles and the aorta and pulmonary artery

  Prevent blood flowing back into the ventricles