Cardiac Electromechanical Activity Flashcards
What is the major ion controlling cardiac resting membrane potential?
EC K+
What ion interaction is responsible for the cardiac action potential?
- Ca entering cell via L-type channels
How do catecholamines affect excitation-contraction coupling?
- Increase Ca Movement into cell by phosphorylation of sarcolemma calcium channels via cAMP-dependent protein kinase
What is the affect of cardiac glycosides?
- Raise IC Na+ w/ effect of increasing contractile force
What is the affect of calcium antagonists?
prevents calcium from entering
the cell, decreasing contractile force.
Compare PKA vs Phosphlambin.
- PKA Phosphorylates Ca channels in sarcolemma + causes inc entry Ca into cell + Contraction
- Phospholambin: phosphorylated by PKA to facilitate relaxation
Differentiate hyperdynamic and hypodynamic heart.
Hyperdynamic: Reduced EDP, Fast rising VP, brief EF
Hypodynamic: Elevated EDP; Slow rise VP; Reduced EF
What does the slope do the ascending limb of VP curve?
Maximal rate of force by ventricle
How do Ionotropic affect Frank-Starling?
INC Inotrophy —> Shifts right
DEC Inotrophy —> Shifts left