Skeletal Muscle Excitation Flashcards
in what order do muscle contraction, nerve AP, and muscle AP occur?
nerve AP
muscle AP
muscle contraction
what channels are located at the bottom of the subneural cleft?
voltage gated sodium channel
what channels are located at the top of the subneural cleft?
ligand gated (Ach) sodium channel
local depolarization opens what type of Ca channels?
voltage-gated
an increase in cytosolic ____ triggers the fusion of presynaptic vesicles containing ____
Ca++
Ach
where are DHP (dihydropyridine) receptors located?
t-tubule
what is the DHP receptor?
voltage sensor
where is the ryanodine receptor located?
covering Ca++ channel
when an AP moves along the T-tubule, the voltage change is sensed by the ____
DHP receptor
when an AP moves along the T-tubule, the voltage change is communicated by the ____
ryanodine receptor
what is the function of the ryanodine receptor?
voltage activated Ca++ release from SR in skeletal muscle
(directly connected to DHP receptor)
what happens when voltage activated Ca++ release from the SR occurs?
skeletal muscle contraction
after muscle contraction occurs, what happens to Ca++?
Ca++ pumped back into SR and binds to calsequestrin to facilitate storage
a single contraction of skeletal muscle is most likely to be terminated by…
removal of sarcoplasmic Ca++ (pumped back into SR by primary Ca pump in SR membrane)
