Cardiac Electromechanical Activity Flashcards
1
Q
What is the major ion controlling cardiac resting membrane potential?
A
EC K+
2
Q
What ion interaction is responsible for the cardiac action potential?
A
- Ca entering cell via L-type channels
3
Q
How do catecholamines affect excitation-contraction coupling?
A
- Increase Ca Movement into cell by phosphorylation of sarcolemma calcium channels via cAMP-dependent protein kinase
4
Q
What is the affect of cardiac glycosides?
A
- Raise IC Na+ w/ effect of increasing contractile force
5
Q
What is the affect of calcium antagonists?
A
prevents calcium from entering
the cell, decreasing contractile force.
6
Q
Compare PKA vs Phosphlambin.
A
- PKA Phosphorylates Ca channels in sarcolemma + causes inc entry Ca into cell + Contraction
- Phospholambin: phosphorylated by PKA to facilitate relaxation
7
Q
Differentiate hyperdynamic and hypodynamic heart.
A
Hyperdynamic: Reduced EDP, Fast rising VP, brief EF
Hypodynamic: Elevated EDP; Slow rise VP; Reduced EF
8
Q
What does the slope do the ascending limb of VP curve?
A
Maximal rate of force by ventricle
9
Q
How do Ionotropic affect Frank-Starling?
A
INC Inotrophy —> Shifts right
DEC Inotrophy —> Shifts left
