blood vessels Flashcards
(10 cards)
list the blood vessels in size order
(smallest–> largest)
1) veins
- carry blood back into heart
2) venules
- carry blood from capillaries to veins
3) capillaries
- connect arterioles to veins
4) arterioles
- smaller than arties and connect to capillaries
5) artieries
- carry blood away from heart into arterioles
moving outwards, describe the structure of a blood vessel
endothelium, elastic fibres, smooth muscle, collagen
what is the name of the inner lining of blood vessels?
endothelium
describe the structural adaptations of the arteries
1) thick muscular walls
- withstands high pressure of the blood
2) elastic tissue
- contains elastin that allows them to stretch and recoil
- maintaining blood pressure
3) small lumen
- helps maintain high blood pressure
4) contain collagen
- provides strength
- to prevent vessel bursting
- maintains vessels shape
what are the elastic fibres made of in blood vessels?
elastin
explain how an arteriolar can reduce the blood flow into capillaries
- muscle contracts
- lumen constricts blood flow
describe the structural adapations of the capillaries
1) lumen is very narrow
- allows red blood cells to be close to body cells
2) walls are thin
- creates short diffusion pathway for exchange of substances
3) highly branched
- provides large surface area for diffusion
describe the structural adapations of veins
1) wide lumen
to maximise volume of blood carried to heart
2) little smooth muscle, or elastic fibre
- not needed due to low pressure
- allows veins to be easily compressed, aiding flow of blood
3) valves
- close to prevent blood flowing backwards
describe the structural adaptations of the arterioles
1) larger lumen than arteries
2) more smooth muscle, less elastin
unlikley to be asked this in exam
describe the structure of function of the venules
- smaller than veins
- very thin walls
- very little smooth muscle
- have valves
