Zusammenfassung der Ressource
blood vessels
- artery
- elastic layer
- thick
- keeps blood pressure high
- stretch and recoil prevents surges in pressure
- overall to resist bursting under pressure
- muscle layer
- thick
- smaller arterioles can be constricted + dilated
- control volume of blood passing through
- most pressure is absorbed by artery walls so less elastic fibres
- valves/lumen
- no valves as blood never flows backward bc of high pressure
- vein
- muscle layer
- thin
- carry blood from tissues, cant control it and slower
- elastic layer
- thin
- blood pressure is low, no recoil action
- valves/lumen
- semi-lunar valves throughout
- pressure is low so prevents backflow
- capillary
- numerous and highly branched + high SA
- penetrate all organs and tissues
- exchange between blood and cells
- collects in venues then returned to veins
- from arteries then arterioles
- one cell thick endothelium = short DD + rapid diffusion
- allows metabolic exhange
- between blood and tissue fluid
- flow of blood is much slower