week 2 : neuronal development and K+ channels

Question 1

what is the relative concentration of K+, Na+ inside and outside cells and why

Answer 1

K+ high iniside
Na+ high outside low inside
as effcts of Na+/K+ ATPase

Question 2

how does AP travel along a neurone?

Answer 2

slatatory conduction
nodes of ranviea

Question 3

what channels are open at different stages of the neuronal action potential

Answer 3

Na+ upstroke
nothing open at peak
K+ open repolraistion long with Na+/K+ ATPase
hyperpolaration then resting potential

Question 4

how does the voltage sensor work on K+ channels?

Answer 4

S3 is divided into AB helixes
moves extracellular portion outward to open pore
or
two opposing subunits move paddle out

Question 5

how many states of activation does K+ channels have?

Answer 5

4
close - both gates
closed - one gate open
open
inactivated

Question 6

how does volatge sensor incatiavtion happen in K+ channels?

Question 7

What happens to the numbers and phosprolyation state of Kv3.4 channels in pain

Answer 7

upregulation of PKC so more phospraation and rudeced surface expression of K + channels less hyperpolariation and hence more painq

Question 8

what happens to the firng of a nurone after injury

Answer 8

acutley - more spontanous firing - decreased expresstion of KV1 channels
cronically - less spontaous fireing ( still more than unijuerd as changes in channel experssion

Question 9

mechism of stimulus secreation in panceratic cells?

Answer 9

increased glucpse - reduced ADP to ATP ratio
more ADP binding to KATP channels
closing of channel
depolariatiom
vgcc open and cuases vesclei binding and insulin relase

Question 10

what happens if there is a gain of fuction mutaion in k+ channls to insulin control

Answer 10

gain of fuction hyperglycacimea
loss of fuction - hyperinsulinism