Lecture 13 - Cardiac Muscle Physiology II Flashcards Preview

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Flashcards in Lecture 13 - Cardiac Muscle Physiology II Deck (10):
1

Modulators of Force?

rate of automaticity, dimensions of ventricle, NT's for rate and Ca2+, inotropic drugs

2

Modulating strength of contraction?

altering Ca transient and myofilament Ca2+ sensitivity

3

Sarcomere length and contractive force?

max overlap following actin filament collision gives maximal force

4

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

5

Parasympathetic (Vagal) effect?

decrease SA node discharge rate & therefore force

6

Sympathetic effect?

increase SA node discharge rate, increase intracellular Ca, increase SR pump rate, decrease sensitivity of troponin for Ca

7

Cardiotonic steroids?

increased intracellular NA by inhibiting NA pump, reducing Ca extrusion via NCX (effective, but with ide effects)

8

Sympathomimetics?

act via beta-1 receptor (limited by desensitisation)

9

Bipyridines?

act via phosphodiesterases

10

Reversing increase of heart dimensions?

nitric acid to relax vasculature, diuretics to decrease blood volume, ACE inhibitors to depress angiotensin axis