Membrane Potential as Signals

Question 1

In general, what do changes in membrane potentials communicate information

Answer 1

communicate information

Question 2

Changes in membrane potential are produced by: ______in ion concentrations in extracellular and intracellular _______. this is NOT involved in ______ transfer

Answer 2

alterations
fluid
information

Question 3

Changes in membrane potential are produced by: changes in membrane ______ to an ion. this IS involved in _____ transfer. produces 2 types of signals:

Answer 3

permeability
information
graded and action potentials

Question 4

Depolarization means what is inside the cell?

Answer 4

becoming less negative aka positive

Question 5

more negative inside the cell means?

Answer 5

hyper polarization (below resting membrane potential)

Question 6

repolarization means?

Answer 6

moving from a depolarization (more positive internal environment) back to a regular resting membrane potential

Question 7

Graded potentials most often occur where?

Answer 7

the dendrites of cell bodies of neurons

Question 8

where are chemically gated channels located?

Answer 8

the dendrites of cell bodies of neurons

Question 9

graded potentials are referred to as graded because?

Answer 9

the magnitude varies directly with stimulus strength

Question 10

are action potentials graded?

Answer 10

no

Question 11

graded potentials are _______ lived ______ changes in membrane potential that don’t travel _____ _____

Answer 11

short-lived, localized

Question 12

changes in polarization ______ in magnitude over distance

Answer 12

decrease

Question 13

threshold stimulus or localized change is a

Answer 13

graded potential

Question 14

In graded potentials: 1. a stimulus ________ small area of neurons membrane.
2. ions flow between the depolarized membrane area and the _______ areas.

Positive ions move ______ more negative areas.
Negative ions move ____ more positive areas
change is _____through leakage channels: this is why it does not go ____ ____

Answer 14

depolarizes 
polarised 
toward 
toward 
lost
very far

Question 15

Action potentials are the _____ method of communication between neurons

Answer 15

primary

Question 16

Action potentials are a _____ reversal of _____ potential

Answer 16

brief, membrane

Question 17

An action potential rises to ____ MV

Answer 17

+30

Question 18

Action potentials occur in _____ _____ channels in cell ____and ____

Answer 18

voltage-gated

cell body, axon

Question 19

Action potentials ____ _____ decrease in size with distance

Answer 19

do not

Question 20

Action potentials can only occur in _______ and ______ cells

Answer 20

neurons and muscle cells

Question 21

Action potentials require a ______ to be met

Answer 21

threshold

Question 22

Action potentials are always the ______ ____ no matter what the size of the graded potential as long as it reaches a threshold.

Answer 22

same size (same magnitude)

Question 23

Graded potentials are different in ________

Answer 23

magnitude

Question 24

neurons send signals over long distances by generating and propagating ____ _____

Answer 24

action potentials

Question 25

most action potentials generate in the _____ ____ | of the initial _____. it then travels the _____ length of the axon

Answer 25

axon hillock segment enitire

Question 26

during action potentials, ____ _____ channels open and close altering the ______ membrane. a voltage stimulus changes the activation gates causing them to open.

Answer 26

permeability

Question 27

repolarization restores resting ______ conditions in either side of the membrane

Answer 27

electrical

Question 28

repolarization does ____ restore resting _____ conditions

Answer 28

not, ionic

Question 29

what helps maintain ionic distributions during rest? (aka return concentrations after repolarization

Answer 29

sodium-potassium pumps

Question 30

Propagation of action potentials are through 1. ________ ______. Depolarizing current flows to sext segment being it to threshold witch leads to regeneration of ____ _____ in a new region. Voltage-gated NA+ inactivate and voltage-gated K+ open. _____ way propagation of nerve impulse

Answer 30

unmyelinated axons action potential one

Question 31

myelinated axons are what type of conductions? _____ ______. these conductions are ___ ____ and action potentials are _____at each node. the spaces in between the myelinated sheaths on the axons are called _____ of ______ where action potentials are _______ due to the presence of ____ ____ Na+ channels. (mostly absent outside of nodes)

Answer 31

``` saltatory conduction very fast, regenerated nodes of Ranvier regenerated voltage-gated ```

Question 32

action potentials are ____ or note

Answer 32

all

Question 33

threshold - depolarization of ___-___mv from resting and requires more ____ entering the cell than K+ _____. This is affected by the strength of ____ graded potential (local current)

Answer 33

15-20 Na+ leaving

Question 34

graded potentials ____ over time

Answer 34

degrade

Question 35

strength of stimulus affects the magnitude of _____ potentials

Answer 35

graded

Question 36

the weak stimulus will ______ before threshold can be reached

Answer 36

degrade

Question 37

Absolute refractory period means

Answer 37

we have already generated/still occurring action potential

Question 38

relative refractory period

Answer 38

no action potential occurs due to the cell being in the hyperpolarization stage. however, this requires a strong stimulus

Question 39

hyperpolarization makes it harder for an action potential to propagate because?

Answer 39

are farther way from the threshold

Question 40

why do stronger stimuli cause more frequent action potentials? what phase can this occur? what refractory period is this?

Answer 40

we are not waiting for the membrane to return to baseline before then jumping again to the threshold hyperpolarization phase relative refractory period

Question 41

Axon diameter: larger diameter axons means

Answer 41

faster impulse conduction

Question 42

Axon diameter: has a larger degree of myelination: | a larger Degree of myelination: insulates and prevents _____ of charge.

Answer 42

leakage