Circulatory System - Blood Vessels

• Circulatory System


  Blood Vessels
• Blood Vessels


  • Designed for their function
• Types of blood vessels

  • Arteries
  • Capillaries
  • Veins
• Arteries


  • Carry blood away from the heart
  • Walls are strong and elastic
  • Walls are thick compared to lumen
  • Contain thick layers of muscle and elastic fibres
• Capillaries


  • Really small
  • Thin walls, only one cell thick
  • Very small lumen
  • Permeable walls to allow exchange of substances
  • Supply food, oxygen and remove waste
• Veins


  • Carry blood to the heart
  • Walls don't need to be as thick as arteries
  • Bigger lumen than arteries
  • Have valves to keep blood flowing in the right direction
• Calculating rate of blood flow

  Volume of blood / Number of minutes