l7 Flashcards
na+ atpase pump Na+ in or out
out
k+ atpase pump k+ in or out
in
true or false leakage channel always open
true
leakage channel also call
non-gated channel
going k+ out with what driving
chemical force
going in k+ with what force
electrical force
Rmp na+ or k+ dominated
k+
what happen when cell reach threshold
action potential fire
na+ moving inside -> depolarise
voltage gated na+ channel opens
right after a bunch of na+ rushed in, what happen to vgsc
inactivated, close, cannot be reopen
when vgsc reopen?
at rmp when cell repolarise again
3 stages of vgsc
closed, open, inactivate
hodgkin cycle
process of lots of depolarise and close channel and trigger more channel and depolarise,… etc
happen after na+ get inside enough
low or high current density there is no hodgkin cycle?
low
low or high current density there is hodgkin cycle?
high
local depolarise activate neighour vgsc
trigger zone call?
axon hillock - high density of vgsc
cell repolarise with what channel
K+
which open later, more slowly, also close slowly Ido not inactivate)
ap for a given neuron
same size and velocity
refracrtory
mean cannot get another one ap after a certain amount of time no matter how hard try
relative refractory
can get another ap but need bigger( 2 reason>?) depolarising stimuli
to propagate along axon, ap needs to overcome?
- loss of local circuit by ion leakage channel
- axoplasmic resistence to the flow of depo;arizing current
- large amounts of charge stored on membrane at rest must be discharge (electrical resistance)
narrow tube more or less resistsnce
more
wider tube more or less resistance
less
