Action potential part 2

Question 1

What are action potentials?

Answer 1

Process by which an electrical impulse is generated, driven by changes in voltage across the membrane of the neuron.

Question 2

What makes a neuron fire?

Answer 2

When dendrites receive input/signal from another neuron

Question 3

In order for an action potential to occur there needs to be a disturbance with the ___________________

Answer 3

Resting potential

Question 4

Membrane potential is more positive than it was at resting membrane potential.

Make it more positive / less negative

Answer 4

Depolarization

Question 5

Membrane potential is more negative than it was at resting membrane potential.

Answer 5

Hyper-polarization

Question 6

In order to understand what happens to the cell during the resting potential we must understand what is happening inside and outside of the _______________

Answer 6

Membrane

Question 7

Intracellular fluid is called ___________

Answer 7

Cytosol

Question 8

Extracellular fluid is called ___________

Answer 8

Interstitial

Question 9

The membrane potential is

Answer 9

The charge of the cell at rest. (When there’s no stimulation going on)

Question 10

Typically the membrane potential is between

Answer 10

-65 to -75 m

Question 11

Why is the charge negative on membrane potential?

Answer 11

Because we have a constant influx and efflux of ions in and out of the cell at rest even when the cell is not being stimulated

Question 12

They key ions of the maintenance of the membrane potentials are

Answer 12

K+= Potassium
NA = Sodium

Question 13

If the resting membrane potential is negative or if the charge inside of the cell is less than the charge outside of the cell we must know that we are losing more positive ions than we’re gaining into the cell in order for that charge to be negative

Question 14

Sodium & Potassium plays a role in this type of polarization of ions

Answer 14

Depolorization

Question 15

The sodium potassium pump’s jobs is to

Answer 15

maintain resting membrane potential and ensure that its negative

Question 16

Potassium plays a role in the type of polarization of ions

Answer 16

Hyper-polorization

Question 17

All membranes have ion channels that allow specific ions to pass though . What are they?

Answer 17

1.Non-gated
2.Open-gated

Question 18

Define non-gated (open)

Answer 18

Channels that are always open and are not influenced significantly by extrinsic factors. They maintain the resting membrane potential.

Question 19

Define Gated (closed)

Answer 19

Channels open and close. In response to specific electrical, mechanical and chemical signals.

Question 20

Transient current flow and therefore rapid changes are made possible by

Answer 20

ion channels in the membrane

Question 21

The effects of the gates will supersede

Answer 21

Sodium and Potassium pumps

Question 22

If you have an electrical , mechanical signal it can trigger this gate to open or close

Answer 22

Gated

Question 23

Voltage gated channels

Answer 23

based on voltage or electrical signal

Question 24

Describe the process of the action potential:

Answer 24

1.Resting potential is stimulated by signal
2.Opening of voltage gated sodium channel to allow sodium to rush into the cell
3. De-polarization using sodium and potassium
4.Once you hit the threshold , all sodium channels open and cell will begin to rapidly polarize
4. Rapid depolarization is what sending the signal
5. Action potential peak
6.When we’ve gotten enough positive charge and after the peak, we resolve the signal by shutting voltage gates for sodium and open up potassium voltage gates instead
7.This causes re-polarization to occur.
8.The cell can go back to its rest state or it can be hyper-polarized
9.This occurs when the membrane potential is more negative than it was at rest.
10.Refractory period
11.Sodium and Potassium pumps bring it back to mrp -70mv

Question 25

What is the threshold for positive ions in an action potential voltage?

Answer 25

-55 mv

Question 26

What is the threshold in the process of the action potential?

Answer 26

the point that the action potential occurs

Question 27

What needs to occur for an action potential to happen ?

Answer 27

The threshold needs to be hit and depolarization happens

Question 28

Moderate or strong signals will hit the

Answer 28

Threshold

Question 29

Week signals do not

Answer 29

Generate action potentials and are failed initiatives

Question 30

All or none principal means

Answer 30

If neuron is sufficiently stimulated it fires, sending the action potential down to the axon and releasing chemicals. The action occurs or it doesn’t

Question 31

Refractory period refers to the

Answer 31

function of hyper polarization when the membrane potential is below the resting state

Question 32

0 Excitability happens during the _______________ because there’s no chance that the nerve cells are going to fire.

Answer 32

Absolute refractory period

Question 33

What are the 2 types of refractory periods?

Answer 33

Absolute and Relative

Question 34

Excitability increases during the _______________ period meaning we’ll be able to generate another action potential because we are closer to resting membrane potential.

Answer 34

Relative refractory period

Question 35

The further you are from the threshold is the harder it will be to generate an action potential.

What principal is that

Answer 35

All or nothing

Question 36

All or nothing principal govern the ________ period

Answer 36

refractory period

Question 37

Where are the voltage-gated ion channels located in the cell?

Answer 37

Great job! The voltage-gated ion channels are located at the axon hillock and along the axon

Question 38

True or False ?

The presence of myelin insulates the axon, which increases action potential speed

Answer 38

True