Lecture 16

Question 1

2 action potential position

Answer 1

start at initial segment
propagate down the axon to the presynaptic terminal

Question 2

voltage gated Na channel

Answer 2

reason for threshold “all or not” event
selectively permeable to Na
resting potential: close, cause little permeability to Na at resting potential
membrane potential: open
inactivate: another gate swing in and plug up the channel

Question 2

threshold potential

Answer 2

depolarize = more positive
hyper polarize = more negative
all or no event

Question 3

action potential process

Answer 3

regenerative

+ FB loop

whether the channel open depend how depolarized the membrane is

more Na flow in, inside more +, more Na channel open, more depolarize, more Na flow in…

Question 4

voltage gated K channel function

Answer 4

open when voltage gated Na channel deactivated

Question 5

voltage gated K channel significance

Answer 5

K can both leak out through leak channel and the voltage gated channel, action potential fall faster, send information faster

Question 6

move along axon process

Answer 6

trigger action potential at initial segment
potential spike up
+ at initial segment & - at adjacent region attract
Na diffuse to the adjacent region
depolarize, propagate, hit the threshold