Blood Vessel Structure Related to Function

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  • Created by: cmulli16
  • Created on: 01-06-15 11:06

Arteries/ Arterioles

Tough Outer Collagen Layer

  • The outer collagen layer is tough and prevents the artery from rupturing at high pressure

Thick layer of Elastic Fibres

  • elastic tissue stretches under pressure when the heart contracts
  • it then recoils
  • this evens out blood pressure/blood flow

Thick layer of Muscle

  • The muscle contracts
  • this reduces the diameter of the lumen
  • in this way the artery can change blood flow/ pressure

Epithelium

  • epithelium is smooth which reduces friction so there are fewer blood clots
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Veins & Capillaries

Veins

  • same collagen layer as arteries
  • they have a wider lumen than equivelent arteries
    • This is because they have less elastic and muscle fibre in their walls
    • they have less of this tissue since they don't need to accomodate high pressure as blood pressure in the veins is low
    • this is because they are carrying blood to the heart, rather than away from it
    • Veins also contain Valves to prevent backflow of blood
    • Same endothelium

Capillaries

  • have no outer layer of collagen fibres
  • Capillaries have no muscle or elastic tissue since they don't accomodate high pressure
  • Capillaries have a very thin endothelium which decreases the diffusion pathway, making them adapted for gas exchange via diffusion.
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