cvs 4 previous semester Flashcards
BF to an organ is proportional to its metabolic activity. IE more blood flow to exercising muscles is an example of
active hyperemia
is an increase in blood flow to an organ to occurs after a period of occlusion of flow
reactive hyperemia
what three organs exhibit auto-regulation
heart, brain, kidneys
blood flow to an organ remains constant over a wide range of perfusion pressures- this is called
auto regulation
what is used to explain autoregulation
myogenic hypothesis
vascular smooth muscle contracts when it is stretched
myogenic hypothesis
example of myogenic hypothesis
increase perfusion pressure to an organ increases stretch of vascular smooth muscle leads to contraction. the resulting vasoconstriction will maintain a constant flow.
tissue supply of 02 is matched to tissue demand for 02
metabolic hypothesis
in metabolic hypothesis vascular metabolites are produced as a result of metabolic activity in tissue. what are the vasodilators
c02
H+
K+
adenosine
during exercise the increase metabolism leads to what
increase production of vasodilators, increase blood flow, increase 02 delivery to the tissue
increase sympathetic tone causes
vasoconstriction
decrease sympathetic tone causes
vasodilation
what is bradykinin similar to
histamine
what causes arteriolar constriction helps to prevent blood loss
serotonin 5-ht
what is implicated in the vascular spasm of migraine headache
serotonin 5ht
what are the effects of histamine
arteriolar dilation and venous constriction leads to increased capillary hydrostatic pressure and increased filtration out of the capillaries resulting in local edema
how does histamine create local edema
artery dilation venous constriction
increase cap hydrostatic pressure
increased filtration out of the capillaries
prostacyclin is a
vasodilator
thromboxane A2 is a
vasoconstrictor
what do baroreceptors do
alerts brain in case of low blood pressure
what are baroreceptors
stretch receptor
where are baroreceptor located
carotid sinus near the bifurcation of common carotid arteries