Neuro Lec 10-13

characteristics of the NMJ:

• small size

• accessible and relatively simple

• synaptic portions of 3 cells: MNs, muscle, Schwann

• high concentrations of things that are at low concentrations extrasynaptically

NERVE action potential at the ____ ____ opens voltage-gated ____ ____

Ca2+ influx triggers ____ ____ ____ to presynaptic membrane and Ach ____

after Ach release, Ach diffuses across the ____ and binds to ____

____ moves in and ____ moves out

this causes postsynaptic membrane ____

after depol, if the ____ ____ voltage is reached, Na+ channels ____, and muscle AP ensues

which of the following is false

• presyn nerve terminal is filled with synaptic vesicles with ACh

• postsynaptic muscle membrane has a high degree of folding

• NMJ is covered by terminal Schwann cells

• NMJ does not cover terminal

which are true

• postsynaptic depol > EPP

• EPP > AP threshold triggers opening of voltage-gated Na+ channels

• EPP - AP threshold = safety factor (ensures that EPP reliably activates myofibre)

• EPP depol myofibre > required for AP threshold

Answer explanation

postsynaptic depol = EPP

ACh is ____ + ____, catalyzed by ____ (short form)

choline comes from extracellular fluid (transported by CHT1)

acetyl-CoA comes from mitochondria

• true

• false

ACh is packed into ____ by VAChT

• secretory vesicles

• mitochondria

• synapses

• NMJs

2-10% of ACh vesicles form the ____ ____ pool, which localize at ____ zones and are released upon arrival of ____ ____ and ____ influx