In working myoctes, phase 0 of AP is rapid depol caused by ___
In working myoctes, phase 1 of AP is initial repol caused by ___.
• I(to)- transient K+ out
• decr I(Na)
In working myoctes, phase 2 of AP is plateau caused by ___.
• transient incr I(Ca2+)- inward
• incr K+ out
In working myoctes, phase 3 of AP is rapid repol caused by ___.
• 1º incr K+ out
• decr Ca2+ in
In working myoctes, phase 4 of AP is resting membrane potential maintained by ___.
In nodal pacing myocytes, phase 0 of AP is upstroke caused by ___
• incr Ca2+ conductance- inward
• note that this is different; I(Na) in working myocytes
In nodal pacing myocytes, phase 1 of AP is ___.
In nodal pacing myocytes, phase 2 of AP is ___.
In nodal pacing myocytes, phase 3 of AP is repolarization caused by ___.
• incr K+ conductance- outward
In nodal pacing myocytes, phase 4 is slow repol (diastolic depol) caused by ___.
• I(f)- inward Na+
I(f) is turned on by ___.
repol of memb potential in preceding AP.
Parasympathetic ___ innervation is found in the SA, artia, and AV.
PS vagal innervation uses the NT ___ on ___ receptors.
Beta-1 receptor activation causes ___ in the CV system.
• positive chronotropy
• pos dromotropy
• pos inotropy
Alpha-1 receptor activation causes ___ In the CV system.
skin, splanchnic, and skeletal vascular smooth muscle constriction
Muscarinic receptor activation causes ___ in the CV system.
• neg chronotropy
• neg dromotropy
• decr atrial inotropy
Neg chronotropy reduces HR by ___.
decr rt of phase 4 depol in pacemaker cells
Decr phase 4 rt in pacemaker cells is caused by ___
decr I(f)- the inward Na+
Neg dromotropy reduces AV nodal conduction velocity by ___
• decr inward Ca2+ current
• incr outward K+ current
___ is the NT that acts on beta-1 receptors
Norepi incr inward Ca2+ during plateau via beta-1 receptors. It also incr SR Ca2+ pump activity by ___, which incr Ca2+ in SR.
phosphorylation of phospholamban
Digitalis has a pos inotropic effect. It inhibits ___ on the myocardial cell membrane.
Na+, K+ -ATPase (causing incr [Na+](intracel))
Digitalis has a pos inotropic effect. It causes incr [Ca2+](intracel) by ___.
diminishing Na+ gradient, which diminishes Na+-Ca2+ exchange
PS (ACh) via muscarinic receptors decr atrial contractility by ___.
decr inward Ca2+ current in plateau
According to the Frank-Starling principle, incr in EDV will cause an incr in ventricular fiber length, leading to ___
incr dev't tension
In other words, Frank-Starling describes a proportional relationship between ___
EDV/RAP and CO/SV
Incr preload causes ___ SV. It is manifest as incr EDV.
Incr afterload causes ___ SV. It is manifest as incr aortic pres
Incr contractility cause ___ SV.