CARDIO 5 Flashcards
what do sympathetic post ganglion fibres innervate
- atria
- ventricles
- SA node
- AV node
what do sympathetic post ganglion fibres secrete
NA
what do parasympathetic post ganglion fibres innervate
- atria
- SA node
- AV node
what do parasympathetic post ganglion fibres secrete
Ach
what does para sympathetic NS cause in SA node
- decrease rate of depol
2. decrease rate of rise to threshold
what does para sympathetic NS cause in AV node
- decrease conduction through AV node
2. increase AV delay
what does para sympathetic NS cause in atrial muscle
- decrease contractility of atrial myocardium
2. decrease force of contraction
what does para sympathetic NS cause in ventricular muscle
none
what does sympathetic NS cause in ventricular muscle
- increase contractility of ventricular myocardium
2. increase force of contraction
what is the overall function of parasympathetic
decrease force and rate of contraction
what is the overall function of sympathetic
increase force and rate of contraction
what is cardiac output
amount of blood pumped by each ventricle in 1 min
what is formula for cardiac output
CO = heart rate x stroke vol
what is stroke vol
amount of blood pumped from each ventricle during systole
how is cardiac output diff from stroke vol
measured in unit time
how can heart rate be altered
modify activity of SA node
how can stoke vol be altered
altering strength of contraction of ventricular myocardium
what does increasing strength of contraction of ventricular myocardium result in
increased stroke vol
what does decreasing strength of contraction of ventricular myocardium result in
decreased stroke vol
what is required to speed up heart rate
- sympathetic stimulation increases
2. parasympathetic stimulation decreases
what is required to slow down heart rate
- parasympathetic stimulation increases
2. sympathetic stimulation decreases
how does increased sympathetic stimulation increase heart rate
- increase release of epinephrine from adrenal medulla
- increase activity of SA node
- increased heart rate
- increased CO
how does increased parasympathetic stimulation increase heart rate
- decreased activity of SA node
- decreased heart rate
- decreased CO
what kind of factors are parasympathetic and sympathetic activity
extrinsic
what does increased sympathetic activity look like on slow AP graph
increase slope of pacemaker potential
what does increased parasympathetic activity look like on slow AP graph
decrease slope of pacemaker potential