cardiac myocyte contractility Flashcards
where is calcium stored
sarcoplasmic reticulum
effect of parasympathetic innervation
decraeses releases of calcium and so decreases contractility
effect of sympathetic
increases release of calcium and so increases contractility
digoxin
Na+/k/atpase
effect of digoxin
decreases sodium gradient and so less calcium is able to be pumped as it relies on energy from the sodium pump
effect of less calcium pumped out
builds up intracellularly, and so inotropy increases
what is digoxin used for
congestice cardiac failure where ventricles cant contract well enoguh
how does sympathetic stimulation increase cardiac contractility
by releasing norepinephrine, which bind to beta 1 receptors on cardiomyocytes
what does norepinephrine bind to
b1 receptors on cardia myocytes
how does the parasympathetic decrease contractility
by releasing ach which bind to m2 muscarinic receptors
positive v negative inotropy
parasympathetic is negative and sympathetic is posiitve
junction sin heart
gap junctions
potassium on membrane potenitla
-90
sodium on membrane potential
+60
resting membrane potentila
-70