circulatory system 2 - blood vessels

• name the 3 main types of blood vessels

  • arteries
  • capillaries
  • veins
• what is the role of the arteries

  arteries carry blood away from the heart (to the lungs, or body tissues)
• what is the role of capillaries

  capillaries exchange substances with the cells of the body (for example oxygen, glucose, and carbon dioxide)
• what is the role of the veins

  veins carry blood towards from the heart (from the lungs, or body tissues)
• which type of blood vessel has valves

  veins have valves
• how are arteries adapted to their function

  function - to carry blood away from the heart

  adaptations:

  • thick muscle layer - to allow them to change their size anadromous direct blood flow (e.g. if the muscle layer contracts, the artery will constrict which will reduce blood flow
  • thick elastic layer - to allow the artery to stretch and recoil, so that blood pressure doesn’t change too much
  • overall thick walls - to make them strong so that they don't burst under the high pressure
• how are capillaries adapted to their function

  function - to exchange substance with the tissues

  adaptations:

  • one cell thick - short distance for diffusion into and out of the capillaries
  • permeable walls - to allow substances to easily move in and out of the capillaries
  • narrow lumen - slows down the blood, allowing more time for diffusion
• how are veins adapted for their function

  function - to carry blood towards the heart

  adaptations:

  • wide lumen - to keep the blood pressure low
  • valves - to prevent the back-flow of blood
• what is the equation to calculate the rate of blood flow

  rate of blood flow = volume of blood (ml) / time (min)
• it takes 6 minutes for 1740ml of blood to pass through an artery. calculate the rate of blood flow through the artery in ml/min

  rate of blood flow = 1740 / 6 = 290 ml/min