Action Potential

Question 1

The nervous system sends both:

Answer 1

qualitative and quantitative information; uses combination of electrical and chemical signals

Question 2

At what part of a neuron are action potentials generated

Answer 2

axon hillock

Question 3

Depolarization means

Answer 3

positive and negative numbers are flipped

Question 4

what do the plasma membrane of the nerve cell body and dendrites (somatodendritic domain) resemble

Answer 4

the basolateral plasma membrane domain of a polarized epithelial cell.

Question 5

What do the plasma membrane of the axon and its nerve terminals resemble

Answer 5

the apical domain of an epithelial cell.

Question 6

where do you see a graded (local) response

Answer 6

1. in dendrites and cell body; only see PASSIVE spread of voltage

Question 7

where do you see an all or none response

Answer 7

from axon hillock to terminus: refers to production of action potentials due to Na and K voltage gated channels

Question 8

What does calcium do

Answer 8

releases neurotransmitters that are stored in nerve termini which bind to receptors on next order neuron w

Question 9

what is hyperpolarization

Answer 9

a membrane potential more negative than at rest

Question 10

what is a hyperpolarizing stimuli due to

Answer 10

either an efflux of cations or an influx of anions

Question 11

What is depolarization

Answer 11

a membrane potential less negative or postive than at rest

Question 12

What is a depolarization stimuli due to

Answer 12

either an influx of cation or an efflux of anions

Question 13

what is threshold potential

Answer 13

the level of depolarization that triggers an action potential

Question 14

what is action potential

Answer 14

a rapid, large regenerative depolarization

Question 15

what is the amplitude of the voltage deflection across the membrane proportional to

Answer 15

the amplitude of the stimulus pulse (the current); the larger the stimulus, the larger the voltage deflection

Question 16

what is resting potential

Answer 16

potential maintained across membrane of excitable cells (neurons, muscle)

Question 17

what is summation

Answer 17

when you inc or dec a graded potential in order to fascilitate or prevent an active potential to be generated

Question 18

Active potential is not summated

Answer 18

True

Question 19

What is graded potential

Answer 19

Does not generate an action potential; its amplitude varies based on strength of stimuli; it can occur all along the axonal domain as long as any depolarization is less than the threshold.

Question 20

Action potentials are:

Answer 20

all or none responses; needs to reach threshold or be above, it cant be below threshold.

Question 21

What type of signal does a graded potential recieve? what about action potential

Answer 21

input; conduction

Question 22

Where does graded potential occur? what about action potential?

Answer 22

dendrites and cell body; trigger zone through axon

Question 23

what types of gated ion channels involved in graded potential? what bout action potential?

Answer 23

Na+, Cl- Ca+; Na and K

Question 24

What type of signal does a graded potential recieve? what about action potential?

Answer 24

depolarizing or hyperpolarizing; depolarizing

Question 25

what are the phases of the action potential

Answer 25

1. rising phase
2. falling phase
3. after-hyperpolarization

Question 26

what is the depolarizing phase

Answer 26

Opens up Na+ channel; starts pouring into cell.

Question 27

What is the repolarizing phase

Answer 27

voltage becomes more neg bc you inactivate sodium channels and you open K+ channels

Question 28

what is the hyperpolarization phase

Answer 28

K+ channels slowly closing, and Na+ channels go from inactive state to closing state.

Question 29

What are three states of voltage gated sodium channels

Answer 29

1. Open
2. Closed
3. Inactive

Question 30

The positive feedback loop associated with the opening of the voltage gated Na channel is known as the:

Answer 30

Hodgkin cylce

Question 31

what does refractory period refer to

Answer 31

unresponsive state; when membrane is refractory its because the voltage gated Na channels are in their inactive state and unable to open in response to a new depolarizing stimulus.

Question 32

what is the one exception to the “all or none” law and the only time you would expect to see a non maximal voltage deflection during an action potential

Answer 32

relative refractory period; a smaller than normal height AP may be generated in response to a larger than usual stimulus.