Ch. 4 Flashcards
(31 cards)
action potentials are similiar in ____ and _____; constant all the way down the axon
size and duration
frequency and pattern of action potentials used by neurons to transfer information
neural code
-65mV to 40mV is known as _____, and occurs _____
depolarization, rapidly
rapid depolarization of membrane
rising phase
when inside of cell is (+) charged
overshoot
rapid repolarization of membrane
falling phase
when internal charge falls below resting potential (-65mV)
hyperpolarization
Na+ depolarizes the neuron, by opening of transmitter-gated Na+ channels
generator potential
if depolarization reaches threshold level at axon hillock then ____ _____ occurs
action potential
firing frequency depends on level of _____
depolarization
1 msec time lag when it is impossible to intiate AP
absolute refectory period
mechanism to artificially control neuron firing
optogenetics
rapid influx of Na+ ions (flows in)
depolarization
efflux of K+ ions (flows out)
repolarization
who discovered most channels flip between open and closed
sakmann and neher
open with little delay (quick rising phase) , stay open for 1msec (brief action potential) , cannot open again until membrane potential repolarizes
Na+ channels
human genetic diseases due to dysfunctional channels
channelopathy
what is the difference between K+ and Na+ channels
potassium channels open later than sodium
potassium opens later to rectify or rest _____ _____
membrane potential
orthodromic propagation (normal)
AP travels down axon to axon terminal
antidromic propagation
backward propagation
how fast an action potential spreads across membrane depends on the ____ _____
axon structure
3 factors of axon structure
diameter, positive charge will take path of least resistance, # of voltage gated sodium channels
A larger axon diameter = _______ spread of depolarization
faster
