blood vessels

• what are the 3 blood vessels

  arteries , capillaries, veins
• what does the arteries do

  carries blood under pressure
• what does the arteries have

  strong and elastic walls , thick walls , thick layers of muscle to make them strong, elastic fibres to stretch and spring back
• what are capillaries 


  arteries that branch into capillaries
• what do capillaries do

  carry blood really close to every cell in the body to exchange substances with them
• what do capillaries have

  thin wall, small lumen, nucleus ,
• what do capillaries supply

  food and oxygen ( take away waste like CO2 )
• why are capillary walls one cell thick

  increases rate of diffusion.
• what do veins do

  take blood back to the heart
• what do veins have

  big lumen( help blood flow) , low pressure, valves , elastic fibres smooth muscle