CIE IGCSE Biology: 复习笔记:9.1.10 Blood Vessels

CIE IGCSE Biology: 复习笔记:9.1.10 Blood Vessels

Arteries, Veins & Capillaries

Arteries

  • Carry blood at high pressure away from the heart
  • Carry oxygenated blood (other than the pulmonary artery)
  • Have thick muscular walls containing elastic fibres
  • Have a narrow lumen
  • Speed of flow is fast

Veins

  • Carry blood at low pressure towards the heart
  • Carry deoxygenated blood (other than the pulmonary vein)
  • Have thin walls
  • Have a large lumen
  • Contain valves
  • Speed of flow is slow

Comparing arteries and veins

Capillaries

  • Carry blood at low pressure within tissues
  • Carry both oxygenated and deoxygenated blood
  • Have walls that are one cell thick
  • Have ‘leaky’ walls
  • Speed of flow is slow

Structure of a capillary

转载自savemyexams

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