ANS and the HEART Flashcards
B1 adrenergic receptor of the heart functions (4)
- helps HCN channels open
- helps t type Ca channels open
- helps L type Ca channels open
- hastens calcium uptake to get ready for next conduction
what nt binds the B1 receptor and what branch of the ANS is it from?
NE…from sympathetic
2 effects of NE binding the B1 receptor?
increase conduction velocity of Aps and increase heart rate
positive chronotropic and dromotropic effects
chrontotropic effect definition
change in heart rate..if increase it is positive
dromotropic effect definition
change in conduction velocity of APs…if faster is positive
ACh binding a muscarinic channel in the heart causes what channel to open?
the potassium channel…hyperpolarizing the cells
ACh has what effect on heart cells?
slows conduction velocity and decreased heart rate
negative dromotropic and chronotropic
when there is a loss of blood volume, what happens to the baroreceptors in the carotid sinus and aortic arch?
they decrease their firing, which is noted by brainstem and ANS is activated
two main roles of the B1 adrenergic receptor for arterial pressure
automaticity and myocardial contractility changes
increases heart rate
if you give a drug that is an agonist of the B1 adrenergic receptor, what is the effect on the heart?
leads to increased cAMP that then increases Ca release and increases contraction force…so more stroke volume and higher CO
which of epi and NE does not have affinity for the B2 receptor but does have it for the B1?
Nor Epi
what is A1 adrenergic receptors main role and how does it do it?
increase smooth muscle contraction…by allowing more Ca to be released in the cell leading to more contraction
if you give an antagonist of ACh what is the effect on the heart?
it will increase the heart rate since ACh normall slows it…
what is the target of an agonist or antagonist of ACh and the para?
M receptors
list the 6 receptors of the ANS
a1,a2,b1,b2,M2,M3
main Parasympathetic receptor of heart
M2
Main sympathetic receptor of heart
B1
two drugs that are M2 antagonists and what is their effect on the heart?
atropine and glycopyrrolate
increase the heart rate
B1 agonist drug and its effect on the heart
Dobutamine and increase heart rate
D1 antagonist drugs (2) and effect on the heart
Metprolol, atenolol and decrease heart rate
what are the two receptors that regulate the vessel constriction?
a1 and b2…but more so A1
name the A1 antagonist and its function
prazosin…decreases the smooth muscle contraction…vasodilation…decrease BP
Name the A1 agonist and its function
midodrine and phenlyephrine
they increase constriction of vessel muscle and increase BP
post synaptic role of a2 receptor
smooth muscle contraction
pre synaptic role of a2 receptor
negative feedback from NE that leads to decreased calcium so decreased NE release
name an A2 agonist drug and give its function
clonidine…actually gives anti sympathetic effect because of the negative feedback
what can clonidine treat?
hypertension
where do indirect agonists of ach act?
AChesterase
propanolol effectors
B1 B2 and B3
carvedilol effectors
a1, b1 ,b2, b3
