Blood Vessels

ARTERY structure
1. Thick walls
  1. Withstands high blood pressure
2. Smooth muscle
  1. Alters diameter of lumen - vary blood flow
3. Elastic fibres
  1. Allows walls to stretch and recoil - smooths blood flow
4. Lined with smooth layer of endothelial cells
  1. Low friction surface - eases blood flow
5. Narrow lumen
CAPILLARIES structure
1. Very thin wall (one cell thick)
  1. Allows rapid exchange between blood and tissues
VEINS structure
1. Thin walls
  1. Under low pressure
2. Very little smooth muscle/elastic fibres
  1. No pulse of blood so there is no stretching/recoiling
3. Wide lumen
  1. Large volume of blood and acts as a reservoir
4. Valves
  1. Stops backflow

Resource summary

	Created by Lauren Garner over 7 years ago