Electricity

Question 0

what can drive a neuron to threshold?

Answer 0

sufficient EPSPs

Question 1

what are axosomatic synapses often.

Answer 1

inhibitory

Question 2

in a single ion system what is reversal potential?

Answer 2

synonymous with equilibrium potential

Vm at which no NET flow of particular ion from one side of membrane to other.

Question 3

what does reversal correspond to?

Answer 3

the fact the change of membrane potential on EITHER SIDE OF EQM POTENTIAL reverses overall ion flux direction!

Question 4

at the NMJ what can you say about EPSPs?

Answer 4

they are always supra-threshold IF Ca supply is ample.

Question 5

which channels open to produce EPSPs and which open to produce action potentials and what effect does this have on the currents?

Answer 5

Ach gated (allow K and Na through) 
voltage - gated Na+ channels. 
inward current smaller in EPSP as simultaneous K+ flows out.

Question 6

what is a capacity current?

Answer 6

voltage needed to open Na channels.

Question 7

why does lowering the [Ca] create limiting conditions?

Answer 7

Ca required for vesicle release.

Question 8

how does transmitter release differ at the NMJ and CNS?

Answer 8

NMJ - single AP triggers release of 200 vesicles.

CNS - single AP triggers release of 1 vesicle.