generating an action potential

Question 1

the fluid on either side of the cell membrane differ in charge because?

Answer 1

of their basic ionic compositions

Question 2

A natural affinity exists between anions and ______

Answer 2

cation

Question 3

anions are defined as?

Answer 3

negatively charged ions

Question 4

cations are defined as?

Answer 4

poisitvely charged ions

Question 5

Charges that are positives and positive will _____ each other

Answer 5

repel because like electrical charges repel each other

Question 6

charges that are positive and negatively charged will ______ each other.

Answer 6

attract

Question 7

Sodium is a _______ ion

Answer 7

positive

Question 8

Chloride ions are negative or positive?

Answer 8

negative

Question 9

sodium and chloride will ______ each other?

Answer 9

attract each other because the sodium is positively charged and the chloride is negatively charged.

Question 10

potassium is negative or positively charged?

Answer 10

positively charged

Question 11

Sodium and potassium will ______ each other.

Answer 11

repel each other because they are both positively charged, and like charged ions repel one another

Question 12

What two ions have a high concentration outside the cell?

Answer 12

sodium and chloride

Question 13

What two things are highly concentrated inside the cell?

Answer 13

potassium and other negatively charged protein molecules

Question 14

Define resting membrane potential?

Answer 14

The difference in electrical charge between the intracellular state and the extracellular state of an unstimulated neuron.

Question 15

the extracellular state of a neuron is _______ charged.

Answer 15

positively

Question 16

the intracellular state of a neuron is ______ charged.

Answer 16

negatively

Question 17

the difference between the intracellular and extracellular sides of a neuron is approximately _____ millivolts.

Answer 17

70

Question 18

the interior fluid is of the cell is approximately _____ _____ millivolts relative to the fluid outside of the cell.

Answer 18

minus 70

Question 19

the cell membrane that has a resting membrane potential of 70 millivolts, at rest is ______ and holds the potential to _____

Answer 19

polarized

change

Question 20

the most extremem change from the cell’s resting potential is called?

Answer 20

the action potential

Question 21

describe action potential?

Answer 21

a quick combination of chemical and electrical activity inside and outside of the cell that actually reverses the polarity of the axon cell membrane, the intracellular fluid becomes more positive charge relative to the extracellular fluid after an action potential has occured.

Question 22

how long does an action potential last?

Answer 22

1 millisecond

Question 23

because ions carry an electrical charge. The term _____ _____ describe the difference in electrical charge between barriers.

Answer 23

voltage gradient

Question 24

what two process operate to maintain the resting potential to set the stage for the action potential?

Answer 24

electrostatic pressure

diffusion

Question 25

define electrostatic pressure

Answer 25

the force exerted by the attraction or repulsion of electrical charges

Question 26

describe how diffusion is prevented in the resting potential

Answer 26

the cellular barrier prevents the cations and anions to evenly distribute between intracellular and extracellular.

Question 27

ion channels in the phospholipid bilayer of the cellular membrane are closed to _____ when the neuron is at resting potential?

Answer 27

sodium

Question 28

the neuron has a threshold potential which means what?

Answer 28

any stimulation below the threshold potential results in little or no change in the membrane potential.

Question 29

what are graded potentials?

Answer 29

ultralocalized voltage changes that increase or decrease membrane voltage

Question 30

hyperpolarizations results from what?

Answer 30

when the extracellular fluid becomes more positive because of either an efflux of potassium or an influx of cloride ions.

Question 31

hyperpolarization ______ the membrane voltage, make the membrane more _____ charged.

Answer 31

increases negatively

Question 32

depolarization in an action potential results form what?

Answer 32

an influx of sodium ions, decreasing the membrane voltage and making the membrane more positively charged.

Question 33

What is the source that fuels the sodium/potassium pump

Answer 33

the pump uses most of the ATP that the neuron produces

Question 34

Describe the function of the Na/K pump affecting the cell membrane

Answer 34

This pump comes into play when the K+ pumps continue to dump too much potassium out of the cell causing Hyperpolarisation (-90, the cell is more negative). This pump activates to regain a resting potential for the cell, inforcing the cell to have only 2 K+ intracellularly and 3Na+ extracellularly.

Question 35

describe a subthreshold stimulus?

Answer 35

a stimulus that results in some ion channels opening and raising the membrane potential some but not to the threshold and results in no effect is observed.

Question 36

If a stimulus exceeds the threshold for excitation, what happens?

Answer 36

the sodium channels open up and the neuron fires with everything the membrane has reaching +30 mV

Question 37

A neuron must return to its ______ in order to carry out another action potential

Answer 37

resting potential

Question 38

At what rate do neurons fire at?

Answer 38

500 HTZ or 500 times per second

Question 39

How long does each action potential take to occur

Answer 39

2 milliseconds including the refractory period

Question 40

after an action potential takes place, potassium channels are _____ which leads to a neuron approaching what type of state

Answer 40

OPEN resting membrane potential

Question 41

During repolarization, what pressure are operating on potassium movement

Answer 41

electrostatic and diffusion pressures

Question 42

Once potassium chanels reach a resting state of \_\_\_, what mechanism of action occurs next

Answer 42

-70 Potassium channels slowly close allowing slow leakage of potassium to continue, this leads to hyperpolarization

Question 43

During hyperpolarization, what type of charge takes place

Answer 43

an even greater negative charge relative to the extracellular space (K is + and is continuing to move outside of the cell)

Question 44

as potassium continue to shift out of the neuron, it accumilates around the \_\_\_\_\_

Answer 44

Cell membrane

Question 45

In hyperpolarization, potassium accumilated around the cell membrane making it have a ____ charge, until the potassium diffuses away from what mechanism?

Answer 45

Positive this happens by diffusion and electrostatic pressure along with potassium harvesting

Question 46

once the membrane potential reaches \_\_\_\_\_\_\_\_, a second set of voltage gated channels open, releasing potassium out of the neuron. this is known as?

Answer 46

+30 potassium efflux

Question 47

when do potassium voltage gated channels open?

Answer 47

when membrane potential reaches +30

Question 48

when does sodium channels close?

Answer 48

membrane potential reaches +30

Question 49

describe what takes place during absolute refractory period

Answer 49

From threshold to threshold (-55 to -70) causing a total inability for the neuron to respond to any charge/impulse

Question 50

potassium efflux is accelerated by what two forces?

Answer 50

electrostatic pressure and diffusion

Question 51

as potassium efflux occurs during \_\_\_\_\_\_\_, the membrane potential becomes more negative.

Answer 51

Repolarization

Question 52

membrane potential is first reached following depolarization in about ____ millisecond, however, further potassium will leak out called \_\_\_\_\_\_\_\_

Answer 52

1 hyperpolarization

Question 53

what occurs during relative refractory period

Answer 53

occurs after repolarisation threshold is met (-70) and takes place until resting potential is reached. During this time, the neuron may respond to more insistent depolarizing signals

Question 54

What uses the majority fo the ATP the neuron produces?

Answer 54

the Na-Potassium Pump