Neuromuscular Junction Flashcards
In order for an acetylcholine-gated ion channel to open, how many Ach molecules need to attach to its alpha subunits
Two
Anchored to the pre synaptic membrane and associated with synaptic vesicles to which they are tethered by short filaments
Dense bars
What represents the first thing that happens after Ach binds to the ligand gated channels in the sarcolemma?
An end plate potential is created on the muscle fiber
A groove in the surface of the sarcolemma in which the axon terminal makes contact with the sarcolemma
Synaptic gutter
A gap between the axolemma of the axon terminal and the sarcolemma of the innervates muscle fiber
Synaptic cleft (20-30nm wide)
Sarcolemma of the skeletal muscle has what kind of ion channels?
Acetylcholine gated ion channel
The vesicles for acetylcholine are transported to the axon terminal from where?
The Golgi
Where is acetylcholine synthesized?
In the cytosol of the nerve axon terminal
Describe what happens when the action potential arrives at the terminus of the axon
The voltage gated calcium channels open and calcium ions enter the axon terminus.
After an end plate potential is created, the action potential on the sarcolemma moves down the T tubules activating which channels?
Voltage gated Dihydropyridine channels
Dihydropyridine channels activate which receptors that allow calcium to flow into the cytosol?
Ryanodine receptors.
Once calcium ions are released in to the cytosol, they bind to (?) in the sarcolemma causing the “sliding filament” mechanism
Troponin!
Fun fact: ER draw troponin levels to help indicate if someone had an MI. These are time dependent and the higher the level the more likely someone had an MI or tissue damage.
