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Physiology 2130 > The Action Potential > Flashcards

Flashcards in The Action Potential Deck (23):
1

What is the characteristic profile of action potentials

Properties of voltage gated Na and K channels

2

how to neurons use electrical signals?

In the forms of action potentials to communicate with each other

3

How is the communication between neurons done

By propagation of an electrical signal and release of neurotransmitters

4

At rest, the cell membrane is much more permeable to which ion?

K+
- is the main ion the contributes to the RMP value

5

At rest, which ion is the cell membrane slightly permeable to?

Na+

6

What controls permeability of a neuron

gated channels

7

What do mechanically gated ion channels do

Open in response to mechanical stimulation

8

What do chemically gated ion channel do

Open in response to a chemical binding

9

What do voltage-gated channels do

Open in response to a voltage change

10

Difference between Na+ and K+ voltage gated channels

Na+ is faster to open where as K+ channel is lazy and slow to close

11

What is depolariztiton

Cell becomes more positive

12

What is repolarization

The depolarized membrane returns to RMP

13

What is the threshold

The minimum depolarization that will initiate an action potential
-55mV

14

What is hyperpolarization

Cell becomes more negative

15

Where to graded potentials occur

neuron dentrites

16

How do graded potential occur

Either depolarization or hyper polarization caused by opening voltage gated channels

17

What is a graded potential proportional to

Amplitude of potential is directly proportional to the stimulus strength

18

What are the 2 reasons why graded potentials can only travel a short distance and lose strength over time

1. Current leak
2. Cytoplasmic resistance

19

In what part of the neuron does the stimulus have to reach in order to generate an action potential

axon hillock with at least -55mV

20

What are the 3 important things about action potentials

1. All or none
2. Unidirectional
3. Always same amplitude and duration

21

What is the absolute refractory period

When a a depolarized cell is returning back to the RMP, no action potentials can be generated until the channels are back to their resting position

22

Which gate is responsible for the absolute refractory period

Inactivation gate

23

What is the loss of K+ through the potassium channel responsible for?

hyper polarization of the cell
-action potentials can be generated here but has to be a strong enough stimulus to push it over the threshold