Blood Vessels

• What do arteries do in the circulatory system?

  Carry blood away from the heart
• Why do arteries have thick, elastic walls?

  To cope with the high pressure of the blood
• What is the function of veins in the circulatory system?

  Carry blood towards the heart
• What feature of veins helps keep blood flowing in the right direction?


  Contain valves
• Why are veins wide in diameter?

  To help blood flow since it is at a lower pressure
• What are capillaries?

  Tiny vessels that carry blood close to every cell in the body
• What is unique about the walls of capillaries?

  They are one cell thick to create a short diffusion pathway
• Why are capillary walls permeable?

  So substances can move across them
• How is the rate of blood flow calculated?

  Rate of blood flow = volume of blood / number of minutes