Blood vessels


There are three different types of blood vessels:


  • Arteries - carry blood away from the heart.
  • Capillaries - where gas exchange takes place.
  • Veins - carry blood to the heart.



  • Carry blood away from the heart.

  • Have thick walls composed largely of muscle and elastic tissue.

  • Have small passageways for blood (internal lumen).

  • Contain blood under high pressure.







  • Carries blood back to the heart.

  • Have thin walls.

  • Have larger passageways for blood (internal lumen).

  • Contain blood under low pressure.

  • Contain valves which stop the blood flowing the wrong way .






  • Found in the muscles and lungs.
  • Walls are one cell thick to allow substances to pass over.
  • Very low blood pressure.
  • Where gas exchange takes place - oxygen passes through the capillary wall and into the tissues, while carbon dioxide passes from the tissues into the blood.



Tags:Blood, vein, artery, arteries, capillaries, red blood cells white blood cells and platelets, red blood cell white blood cell and platelets



© 2012 science-resources.co.uk. All rights reserved | Design by W3layouts