blood vessels

• What are the three main types of blood vessels?

  • Arteries
  • Veins
  • Capillaries
• What is the structure of arteries?

  • Thick muscle layer - to withstand high blood pressure.
  • Thick elastic layer - to allow the pulses of the blood through.
  • Narrow lumen - to maintain the high blood pressure.
• What is the function of arteries?

  To carry blood away from the heart.
• What is the structure of veins?

  • Thin muscle layer.
  • Thin elastic layer.
  • Wide lumen - to allow the blood to flow at a low pressure.
  • Valves - to stop backflow of blood.
• What is the function of veins?

  To carry blood towards the heart.
• What is the function of the capillaries?

  A site of exchange in tissues.