Blood vessels Flashcards
what are pre-capillary sphincters
controls blood flow to specific capillary beds selectively
what is smooth muscle
supplies the vessels with contractile power and regulates lumen diameter
what is the endothelium
filtering interface between blood and the body
what is elastin for
gives vessels mechanical strength and their elastic properties
what is adventitia
provides structural strength and tethers the vessels in place
what are arterioles responsible for
altering the levels of resistance to blood flow in order to distribute the available amount of blood
what do conduits do to divert blood
they change their shape to restrict bloodflow
what is active hyperamia
the increase in blood flow according to the metabolic needs of the tissue in question
what is flow auto regulation
concerns with the maintenance of blood flow rather than changing it, blood to brain has to be maintained for example as to not enlarge
what is myogenic regulation of arterial diameter
increase in pressure leads to muscle stretch that is followed by constriction, myogenic response prevents flow from getting to high
describe capillaries
there are numerous of them all across the body and are one cell thick to facilitate diffusion
what dictates the velocity of blood flow
the total cross sectional area of capillaries not individual capillaries
is the velocity of capillaries high or low
low
where are capillaries found
surrounding every muscle fibre
when does filtration take place
when hydrostatic pressure exceeds colloid osmotic pressure