blood vessels: organisation

• structure of artery

  • thick, muscular, elastic walls
  • thick walls that can stretch and withstand high pressure
  • small lumen
• function of artery

  carries de-oxygenated blood AWAY from the heart TO the LUNGS
• function of veins

  carries oxygenated blood TOWARDS the heart FROM the lungs
• structure of the vein

  • thin walls = can't withstand high pressure
  • large lumen
  • has valves to prevent backflow of blood
• function of capillaries

  carries blood TO tissues AND cells AND connects arteries and veins
• function of capillaries

  • one cell thick- short diffusion distance for substances to move e between BLOOD and TISSUES (O2 in cells, CO2 out)
  • very narrow lumen
• function of venacava

  brings de-oxygenated blood to the heart
• function of right and left ventricle:

  1. right ventricle= pumps blood to the lungs
  2. left ventricle= pumps blood around the body
• what are the blood vessels and coronary artery?

  branch out the aorta and spread out into the heart muscle
• what is the purpose of the coronary artery?

  provide oxygen to the muscle cells of the heart which is used in respiration to provide the energy for contraction
• what is the purpose of an artificial pacemaker?

  Regulate heartbeat.
• where is a pacemaker planted?

  right atrium