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Flashcards in coupling Deck (11):
1

similarities in skeletal and cardiac muscle

1. contraction elicited by increase in myoplasmic calcium concentration
2. intracellular store (SR) is main source Ca2+
3. release Ca2+ originates at t-tubule

2

Cardiac Muscle:
ECC requires

1. entry of external Ca
2. CaV1.2 (α1C)
2. β2a or β2b
3. α2δ1 RyR2

3

Skeletal Muscle: ECC require

1. DOES NOT REQUIRE entry of external Ca
2. CaV1.1 (α1S)
3. β1a
4. α2δ1, γ1 RyR1

4

how does SERCA2 remove calcium

Ca diffuses within SR to terminal cisternae, where it binds to calsequestrin (low affinity, high capacity)

5

why does SERCA2 dominate?

since SR surrounds each myofibril; requires less energy since VSR≈0.

6

cardiac muscle, Ca2+ is released from SR by

RyR2

7

skeletal muscle, Ca2+ is released from SR by

RyR1

8

in both skeletal and cardiac, Ca2+ binds to

troponin on thin filaments and activates contraction

9

Expression of Cav1.1 or Cav1.2 in

dysgenic myotubes

10

Relaxation:

SERCA>NCX>>PMCA

11

NCX driven depolarization, secondary to _____, has been suggested to be important for ____

diastolic SR Ca release

pacemaking of SA nodal cells.