8.2 Flashcards
what are blood vessels composed of?
elastic fibres
smooth muscle
collagen
what are the elastic fibres?
composed of elastin and provide the vessels with flexibility by stretching and recoiling
maintain a high pressure
what is the smooth muscle?
contract and relax to change the lumen size
what is the collagen for?
gives the vessel structure
what do arteries do?
blood away from the heart
what are the arterioles?
link the capillaries and the arteries
what do the elastic fibres do in the arteries?
stretch to allow for more blood to be uptaken
recoil to push blood through and maintain blood flow
what is the composition of arterioles?
more smooth muscle
and
less elastin
than the arteries
what are the properties of the capillaries?
they are one cell thick to allow for a short diffusion distance to maximise gas exchange
have a large SA
forces blood flow to slow to allow time for gas exchange
what do veins do?
carry blood towards the heart
what do veins have to prevent the back-flow of blood?
valves
what do venules do?
link capillaries with the veins
have little muscle
how is blood pumped up?
muscles contract to squeeze the veins which forces the blood up
arteries composition
lots if elastic tissue
less smooth muscle
SMALLER LUMEN
arteries structure
capillaries structure
vein structure
