CV7 Flashcards
what can MAP be altered by
cardiac output
peripheral resistance
what causes small changes in blood volume
ingestion of food and liquid
what normally resolves changes in blood volume
kidneys
where is resistance highest within
arterioles
how to determine where the highest resistance is
area of the curve with the greatest drop
how are arterioles arranged
series and parallels
how are capillaries arranged
parallel meaning that all blood flows through them at the same time
what does local control of arteriolar resistance mean
goal is to match tissues blood needs
what are sympathetic reflexes of arteriolar resistance
CNS maintaining mean arteriole pressure and given blood distribution
what is myogenic auto regulation
a kind of local control
smooth muscle contracting because of an increase of blood flow to an area, constricting the vessel to not overload the capillaries
where do you often see myogenic auto regulation
brain and kidneys
what do arterioles contain
a variety of stretch activated TRP channels that are responsive for the depolarization leading to visceral smooth muscle contracting (myogenic response)
what are the examples of local control
myogenic autoregeneration
paracrine (metabolism related)
what will increased metabolism of a tissue cause ? (higher CO2, lactate, etc)
it will cause the arteriole to relax in order for more blood to come to that area. paracrines are saying the tissue needs oxygen
what are some non metabolism paracrines that alter blood supply
histimine (would signal more blood flow needed - relax arterioles)
serotonin (signals that repair is needed - would constrict vessels)
whats the main determinant of resistance in the majority of arterioles
the sympathetic nervous system and how activated the a1 adrenergic receptor is
how does the sympathetic nervous system (specifically norepinephrine) affect the arterioles
as sympathetic activity increases, the blood vessel constricts in response to norepinephrine on a1 receptors
as it decreases, the blood vessel radius increases
what does epinephrine have a high affinity for ? what does it lead to
b2 adrenergic receptors which leads to vasodilation
50-60% of vascular smooth muscle responds how
innervated by sympathetic neurons releasing norepinephrine onto a1 adrenergic receptors
if blood flow goes up in a region during sympathetic activity, what receptors does it most likely have more of
b2 adrenergic
if blood flow goes down in a region during sympathetic activity, what receptors does it most likely have more of
a1 adrenergic
what are the main determinants of MAP
cardiac output and flow out of arteries
what is bradycardia
slowed heart rate
what is tachycardia
fast heart rate
how does the cardiovascular system regulate itself
by selectively altering blood flow to organs
at rest, what does the regional amount of blood flow depend on
number and size of arteries feeding the organ
total blood flow through all of the arteries = the ___________
cardiac output
blood will always flow through the arteriole with the _________ resistance
least
whats the main integrating centre of the cardiovascular function
Medullary cardiovascular control centre
where is the CVCC
medulla
whats the primary function of the CVCC
ensures adequate blood flow to the brain and heart by maintaining sufficient mean arterial pressure
what does the CVCC have the ability to do
specifically alter function in a few organs or tissues
what drives changes in autonomic output towards target tissues in the cardiovascular system
cardiovascular control centre (CVCC)
