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Flashcards in Action Potential Deck (32):
1

The nervous system sends both:

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

2

At what part of a neuron are action potentials generated

axon hillock

3

Depolarization means

positive and negative numbers are flipped

4

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

the basolateral plasma membrane domain of a polarized epithelial cell.

5

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

the apical domain of an epithelial cell.

6

where do you see a graded (local) response

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

7

where do you see an all or none response

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

8

What does calcium do

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

9

what is hyperpolarization

a membrane potential more negative than at rest

10

what is a hyperpolarizing stimuli due to

either an efflux of cations or an influx of anions

11

What is depolarization

a membrane potential less negative or postive than at rest

12

What is a depolarization stimuli due to

either an influx of cation or an efflux of anions

13

what is threshold potential

the level of depolarization that triggers an action potential

14

what is action potential

a rapid, large regenerative depolarization

15

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

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

16

what is resting potential

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

17

what is summation

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

18

Active potential is not summated

True

19

What is graded potential

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.

20

Action potentials are:

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

21

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

input; conduction

22

Where does graded potential occur? what about action potential?

dendrites and cell body; trigger zone through axon

23

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

Na+, Cl- Ca+; Na and K

24

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

depolarizing or hyperpolarizing; depolarizing

25

what are the phases of the action potential

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

26

what is the depolarizing phase

Opens up Na+ channel; starts pouring into cell.

27

What is the repolarizing phase

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

28

what is the hyperpolarization phase

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

29

What are three states of voltage gated sodium channels

1. Open
2. Closed
3. Inactive

30

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

Hodgkin cylce

31

what does refractory period refer to

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.

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

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