arteries, veins & capillaries Flashcards
2.68
where do arteries carry blood to?
away from the heart
what is the blood like in arteries?
flowing at high pressure
where do veins carry blood to?
return blood into the heart
what is the blood like in veins?
flowing at low pressure
what are capillaries?
tiny vesselsa
are there a lot of capillaries?
yes
where do capillaries carry blood through?
they carry blood through all the tissues
what are capillaries the site of?
the site of exchange of materials by diffusion
arteries:
wall?
lumen?
muscles & elastic fibres?
- thick outer wall
- small lumen
- thick layer of muscles & elastic fibres
what is the function of the artery’s thick outer wall?
can transport blood at high pressure without bursting
what is the function of the artery’s thick layer of elastic tissue?
allows the artery to stretch & recoil to keep blood flowing at high pressure
what is the function of the artery’s thick layer of muscular wall?
helps to control flow of blood by widening (dilating) and narrowing (constricting)
what are arterioles?
smaller vessels that branch off from arteries
what are venules?
small veins
why type of blood do arteries carry?
oxygenated blood
what artery carries deoxygenated blood?
pulmonary artery
at what speed does blood flow through arteries?
at a fast speed
what also helps arteries to maintain high pressure?
a narrow lumen
veins:
wall?
lumen size?
muscle & elastic fibres?
- fairly thin outer wall
- large lumen
- thin layer of muscle & elastic fibres
what type of blood do veins carry?
deoxygenated blood
what type of blood does the pulmonary vein carry?
oxygenated blood
veins contain…
semilunar valves
at what speed does blood flow through veins?
at a slow speed
what does a large lumen do for the veins?
reduces resistance to blood flow under low pressure