Action Potential and synaptic transmission

Question 1

the resting membrane potential arises primarily from …

Answer 1

membrane permeability to K+ ions.

Question 2

the depolarising phase of the action potential is caused by…

Answer 2

influx of Na+ ions entering the cell through voltage gated Na channels

Question 3

The depolarising phase of the action potential is predominately caused by…

Answer 3

efflux of K+ ions

Question 4

One way in which GABA functions is by triggering a hyperpolarization of the post-synaptic membrane when it binds to GABAb receptors.BY which mechanism?

Answer 4

By triggering efflux of K+ .GABA binds to g-protein coupled GABAB receptors which when activated directly open a K+ channel called a GIRK channel-this leads to K+ efflux and hyperpolarisation.GABA also binds to GABAA receptors which open Cl- channels.

Question 5

what ensures that Ca2+ channels open ?

Answer 5

depolarisation of presynaptic membrane

Question 6

what is the definition of an ionotropic receptor

Answer 6

a membrane bound receptor that contains an ion channel