Types and functions of blood vessels

• 3 types of blood vessels

  Arteries

  Capillaries

  Veins
• Arteries

  Transport blood away from the heart under high pressure

  Walls are thick and muscular, to maintain and withstand this pressure

  The lumen (the interior passage of a blood vessel) is small in comparison to its walls
• Capillaries

  Tiny blood vessels where exchange of gas and nutrients occur

  The walls are 1 cell thick

  Oxygen and nutrients pass from capillaries to body cells

  Carbon dioxide and other wastes are collected for removal
• Veins

  Carry deoxygenated blood back to the heart

  Larger lumen than arteries, and thinner walls

  They carry blood at a lower pressure

  They have valves to prevent the backflow of blood