Flashcards in Lecture 13 - Cardiac Muscle Physiology II Deck (10):
Modulators of Force?
rate of automaticity, dimensions of ventricle, NT's for rate and Ca2+, inotropic drugs
Modulating strength of contraction?
altering Ca transient and myofilament Ca2+ sensitivity
Sarcomere length and contractive force?
max overlap following actin filament collision gives maximal force
Effects of increased heat rate?
Less time for Ca2+ extrusion, decrease in membrane potential decreasing efflux via NCX, increased intracellular Ca and NA via NCX
Parasympathetic (Vagal) effect?
decrease SA node discharge rate & therefore force
increase SA node discharge rate, increase intracellular Ca, increase SR pump rate, decrease sensitivity of troponin for Ca
increased intracellular NA by inhibiting NA pump, reducing Ca extrusion via NCX (effective, but with ide effects)
act via beta-1 receptor (limited by desensitisation)
act via phosphodiesterases