A&P of Neuromuscular junction - Rogers

Question 1

a motor unit is

Answer 1

all muscle fibers innervated by a single motor neuron

Question 2

Choline transporter brings choline into the nerve terminal by using what gradient

Answer 2

Na

Question 3

in the cell, choline is combined with what molecule

Answer 3

Acetyl-CoA making choline acetyltransferase (ChAT)

Question 4

ChAT is stored by what enzyme

Answer 4

ACh vesicular transporter (VAT) (ATP dependent)

Question 5

vesicle mobilization is driven by what

Answer 5

Ca2+ induces mobilization (from voltage-gated Ca2+ channels opened from depole)

Question 6

VAMP

Answer 6

vesicular associated membrane protein

Question 7

VAMP and SNAPs do what

Answer 7

initiate docking and fusion of vesicles to PM

Question 8

SNAP

Answer 8

synapse associated protein

Question 9

acetylcholinesterase

Answer 9

breaks down ACh into choline and acetate
choline retaken nto motor neuron
vesicles endocytosed

Question 10

nicotinic

Answer 10

ionotropic
ACh binding transiently increases permeability to Na and K
Na flows in - depolarization
e.g. muscle contractions

Question 11

muscarinic

Answer 11

metabotropic 
ACh binding elicits IC response via G proteins 
initiate wide variety of responses 
generally slower 
Not at Neuromuscular junction

Question 12

muscarinic AChRs (5 subtypes)

Answer 12

M1, M4, M5 - CNS
M2 - heart
M3 - Smooth muscle

Question 13

nicotinic AChRs characteristics

Answer 13

ligand gated ion channels (different isomers have different cation specificities) 
millisecond response time 
4 diff SU arranged in petamer 
Ach binds between a-su and adjacent su 
requires 2 molecules of Ach to activate