How do Neurons Process Information

Question 1

action potentials

Answer 1

brief (transient) but large changes in the membrane potential

Question 2

inside of the membrane during action potentials

Answer 2

for an instant, the inside of the membrane becomes positively charged

Question 3

action potentials triggered

Answer 3

in the axon hillock

Question 4

action potentials conducted

Answer 4

along the axon

Question 5

ion channels can open/close for many reasons

Answer 5

a ligand/chemical can bind a receptor
temperature-sensitive
voltage-sensitive

Question 6

ions flow into/out of cell, alters

Answer 6

membrane potential

Question 7

hyperpolarization

Answer 7

cell becomes MORE negative

Question 8

hyperpolarization anions

Answer 8

flow into cell

Question 9

hyperpolarization cations

Answer 9

flow out of cell

Question 10

depolarization

Answer 10

cell becomes less negative

Question 11

depolarization anions

Answer 11

flows into cell

Question 12

depolarization cations

Answer 12

flows out of cell

Question 13

threshold #1

Answer 13

stimulus causes a small depolarization of the neuron to the threshold voltage (-40 to -55 mV)
failed initiations also happen here
action potential triggered
all-or-none

Question 14

what creates a failed initiation of an action potential?

Answer 14

not enough information coming into the cell body
not positive enough to go from -40 to -55 mV
not big enough to reach the threshold potential

Question 15

depolarization #2

Answer 15

when the interior of the cell becomes positive

Question 16

repolarization #3

Answer 16

when the membrane potential becomes negative

Question 17

hyperpolarization #4

Answer 17

when the membrane potential undershoots the RMP

Question 18

refractory period

Answer 18

neuron cannot generate another action potential until it returns to RMP

Question 19

resting state #5

Answer 19

when the membrane returns to RMP

Question 20

information encoded by ____, not ___

Answer 20

number of action potentials, not size

Question 21

if a neuron wants to send a lot of information:

Answer 21

has to send more action potential, not a bigger action potential

Question 22

RMP

Answer 22

-60 to -70 mV
K+ channels are open
Na+ channels are closed

Question 23

small depolarizing stimulus

Answer 23

generated by positive charge from cell body
causes membrane potential to become less negative and approach threshold potential (-40 mV)

Question 24

at threshold voltage-gated Na+ channels

Answer 24

open/activate (because of change in membrane voltage)
Na+ ions rush into the cell
membrane potential becomes positive

Question 25

after 1 millisecond, the Na+ channels

Answer 25

inactivate
no more Na+ entering cell
absolute refractory period

Question 26

absolute refractory period

Answer 26

reset before they can open again- are locked until reset

Question 27

inactivation

Answer 27

channel closed and temporarily unable to open again

Question 28

as membrane depolarizes, voltage-gated K+ channels

Answer 28

slowly open/activate
“delayed-activating” K+ channels
K+ flows out of cell
membrane hyperpolarizes
relative refractory period
voltage-gated K+ channels close but other K+ channels stay open
Na+ reset

Question 29

Which number corresponds to when Na+ ions enter the neuron?

Answer 29

threshold

Question 30

active propagation of action potential

Answer 30

is slow (10 m/s), but does not weaken
takes many small steps down the axon- some chance of failure at every step

Question 31

passive propagation- myelinated axon

Answer 31

action potential triggered at axon hillock, moves passively through the myelinated segment- quick (150 m/s), but signal weakens as it travels

Question 32

at Node of Ranvier

Answer 32

action potential regains full charge through active means (Na/K channels)
then moves passively through next myelinated segment

Question 33

If someone is exposed to a toxin that blocks voltage-gated Na+ channels, their action potentials will ____
a. get smaller
b. not be generated
c. get larger

Answer 33

b. not be generated