- Carry blood away from the heart and into the arterioles
- Tough fibres outer layer- resists pressure changes within and outside
- Muscle layer is thicker than veins- can be constricted and dilated in order to control the volume of blood passingthrough them.
- Elastic layer is thicker than veins- able to stretch and recoil to maintain high BP
- Thin inner layer- smooth to reduce friction and thin for short diffusion pathway.
- No Valves- due to constant high pressure
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- Smaller arteries that control blood flow from arteries to capillaries
- Tough fibrous outer layer- resists pressure changes
- Muscle layer is relatively thicker than arteries- Retricts blood flow and so controls its movement
- Elastic layer (tinner than arteries)- because the BP is lower.
- Thin enothelium- smooth, reduces friction, short diffusion pathway
- Lumen- blood flows through here.
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- Tiny vessels that link arterioles to veins
- Walls consist of epithelium lining- extremely thin for short diffusion pathway
- Hughly branched- large surface area for exchange
- Narrow diameter- short diffusion pathway
- Lumen is narrow- red blood cells are squeezed flat against the side reduces diffusion distance.
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- Carry blood from the capillaries back to the heart
- Tough fibrous outerlayer
- Thin muscle layer- carry blood away from tissues doesnt cannot control flow of blood
- Elastic layer relatively thin- BP too low to cause recoil action
- Thin epithelium layer- Smooth, and short diffususion pathway
- Valves at intervals throughout to prevent backflow of blood
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