Blood vessels
- Created by: jessicawarren
- Created on: 24-04-16 15:36
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- Blood Vessels
- Arteries
- Carry blood from heart to body
- Walls thick/muscular- control flow of blood, resist pressure changes
- Walls have elastic tissue to stretch/recoil as heart beats- helps maintain high pressure
- Inner lining (endothelium) folded, allows artery to stretch, maintains high pressure, allows diffusion
- All arteries carry oxygenated blood except pulmonary, takes deoxygenated blood to lungs
- Aterioles
- Divisions of arteries
- Form network throughout body
- Blood directed to different areas of demand by muscles inside arterioles
- Muscles contract to restrict blood flow/relax to allow full blood flow
- Veins
- Take blood back to heart under low pressure
- Wider lumen
- Little elastic/muscle tissue
- Contain valves to stop backflow
- Blood flow helped by contraction of body muscles surrounding veins
- All veins carry deoxygenated blood except pulmonary, carry oxygenated blood from heart to lungs
- Capillaries
- Smallest of blood vessels
- Found very near cells in exchange tissues- short diffusion pathway
- Walls one cell thick- short diffusion pathway
- Large number of them- increases exchange surface area
- Network of capillaries: 'capillary bed'
- Venules
- Untitled
- Arteries
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