Muscle Module 4 Flashcards
__________ fuse to presynaptic membrane to release acetyl choline and then defuse to the receptor
synaptic vesicles
The release of _______________ leads to an action potential
100 or more synaptic vesicles
The stimulation in a muscle cell leads to the onset of ______________________
contraction at 10 msec
how does the depolarization of T tubule membrane result in sarcoplasmic reticulum releasing calcium and initiating contraction
microscopy shows feet connecting SR membrane and t tubule that allows them to relay depolarization via proteins involved
What are the two proteins involved in the T tubules
- DHP dehydrophyride receptor DHP: voltage Ca 2+ channels:
- RYR receptor: Ca2+ release channel and receptor
What protein is involved in sarcoplasmic reticulum
-calcium pump protein or serca
Distance between muscle fivers and surface membrane is too big for calcium diffusion to result in a 10 msec action potential, we need another method besides diffusion
transverse tubule
__________ is another name for a muscle fiber membrane
sarcolemma
___________ is a membrane surrounding myofibrils that contains and releases calcium
sarcoplasmic reticulum
we dont need extracellular calcium for contraction thus we need a rich source inside the cell ___________
sarcoplasmic reticulum
what are the steps of excitation
- T tubules depolarize
- DHP R opens
- DHPR mechanically opens RYR
- Ca2+ release from SR
- Ca2+ pumps protein and returns CA to SR
What is the troponin complex
T tnt
I tnt
C tnt
Troponin complex is a calcium sensitive molecular switch that depends on _____________
calcium levels
When calcium binds it exposes _____________
myosin binding site
when calcium is not presensent the configuration
blocks the myosin binding site
