Blood Vessels

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  • Created by: Tre
  • Created on: 28-12-12 12:44
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Arteries Veins Capillaries
Takes blood away from the heart Takes blood to the heart Smallest blood vessel 7-10
Lumen is small this keeps the blood Lumen is large this keeps the blood micrometres same diameter of a RBC
flow under high pressure and rapid so it flow under low pressure and it flows No elastic tissue, smooth muscle or
can get around body slowly collagen fibres
Endothelium (tunica intima) reduces Endothelium (tunica intima) reduces Links arteries to veins to allow gas or
the friction of the blood on the wall the friction of the blood on the wall material exchange between the blood
Elastic tissue (tunica media) is thick Elastic tissue (tunica media) is not as and tissues
because it needs to be able to stretch thick as the artery and is quite thin Slowing of blood flow
when the heart pumps blood and recoil Smooth muscle (tunica media) is thin Endothelium has gaps in it which allows
Smooth muscle (tunica media) is when also as no contraction is needed gas and material exchange to happen
allows the artery to contract and relax Collagen fibres (tunica externa)
Collagen fibres (tunica externa) protects the vein from damage
protects the artery from damage Valves help blood flow in one direction
towards the heart. When skeletal muscles
contract, they squeeze the vein and this
increases the pressure which opens the
valve ahead and closes the one below

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