Ch. 4

Question 1

action potentials are similiar in ____ and _____; constant all the way down the axon

Answer 1

size and duration

Question 2

frequency and pattern of action potentials used by neurons to transfer information

Answer 2

neural code

Question 3

-65mV to 40mV is known as _____, and occurs _____

Answer 3

depolarization, rapidly

Question 4

rapid depolarization of membrane

Answer 4

rising phase

Question 5

when inside of cell is (+) charged

Answer 5

overshoot

Question 6

rapid repolarization of membrane

Answer 6

falling phase

Question 7

when internal charge falls below resting potential (-65mV)

Answer 7

hyperpolarization

Question 8

Na+ depolarizes the neuron, by opening of transmitter-gated Na+ channels

Answer 8

generator potential

Question 9

if depolarization reaches threshold level at axon hillock then ____ _____ occurs

Answer 9

action potential

Question 10

firing frequency depends on level of _____

Answer 10

depolarization

Question 11

1 msec time lag when it is impossible to intiate AP

Answer 11

absolute refectory period

Question 12

mechanism to artificially control neuron firing

Answer 12

optogenetics

Question 13

rapid influx of Na+ ions (flows in)

Answer 13

depolarization

Question 14

efflux of K+ ions (flows out)

Answer 14

repolarization

Question 15

who discovered most channels flip between open and closed

Answer 15

sakmann and neher

Question 16

open with little delay (quick rising phase) , stay open for 1msec (brief action potential) , cannot open again until membrane potential repolarizes

Answer 16

Na+ channels

Question 17

human genetic diseases due to dysfunctional channels

Answer 17

channelopathy

Question 18

what is the difference between K+ and Na+ channels

Answer 18

potassium channels open later than sodium

Question 19

potassium opens later to rectify or rest _____ _____

Answer 19

membrane potential

Question 20

orthodromic propagation (normal)

Answer 20

AP travels down axon to axon terminal

Question 21

antidromic propagation

Answer 21

backward propagation

Question 22

how fast an action potential spreads across membrane depends on the ____ _____

Answer 22

axon structure

Question 23

3 factors of axon structure

Answer 23

diameter, positive charge will take path of least resistance, # of voltage gated sodium channels

Question 24

A larger axon diameter = _______ spread of depolarization

Answer 24

faster

Question 25

smaller axons require ______ depolarization to coss threshold

Answer 25

greater

Question 26

what are the two myelinating cells

Answer 26

schwann cells (PNS) , oligodendroglia (CNS)

Question 27

spike initiation zone (where action potential starts)

Answer 27

axon hillock

Question 28

local alteration in the membrane potential, proportional in size to ion influx

Answer 28

graded response

Question 29

immune attack on PNS (schwann cells) , rapid onset, slow conduction of impulses to muscles in the PNS

Answer 29

guillain- Barre syndrom

Question 30

damage and inflammation limited to the spinal cord

Answer 30

transverse myelitis

Question 31

damage and inflammation limited to optic nerve

Answer 31

optic neuritis