Neuronal Membrane Potential

Question 1

The nervous system continually ___, ____ and _____ information

Answer 1

• Transmit
• Integrate
• Proccess

Question 2

What information travels through an ascending pathway/tract?

Answer 2

Sensory/ Inputs/ Afferent

Question 3

What information travels through a descending pathway/tract?

Answer 3

Motor/ outputs/ Efferent

Question 4

Defined pathways are ____

Answer 4

Networks

Question 5

The response to an input is a Neuron is a result of what?

Answer 5

Change in Membrane Potentional

Question 6

The strength of the input is encoded by a _____________

Answer 6

The magnitude of change in the membrane potential

Question 7

Proteins tend to have what kind of charge?

Answer 7

Negative (Anionic)

Question 8

Membrane potential measure what?

Answer 8

The strength of attraction between ions along the surface of the membrane

Question 9

What kind of ions are typically found on the outer surface of the membrane?

Answer 9

Cations (+)

Question 10

What kind of ions are typically found on the inner surface of the membrane?

Answer 10

Anions (-)

Question 11

What is the typical value of a membrane potential?

Answer 11

-65 mV

Question 12

The sign of a membrane potential indicates what? Ex. -65mV

Answer 12

polarity

Question 13

The number of a membrane potential indicates what? Ex. -65mV

Answer 13

Strength of electrical force

Question 14

A change in membrane potential is caused by what?

Answer 14

redistribution of ions (current)

Question 15

_____ is the movement of ions

Answer 15

Current

Question 16

Channels are dependent on ____

Answer 16

Signals

Question 17

Neurotransmitters are classified as what kind of signals?

Answer 17

Ligands

Question 18

What kind of channel is dependent on the change in membrane potential as a signal?

Answer 18

Voltage-gated

Question 19

_____ is defined as relaying information from location to another with in the body

Answer 19

Transmission

Question 20

____ is defined as adding multiple inputs from multiple sources

Answer 20

Integration

Question 21

____ is the conversions of nervous inputs into outputs

Answer 21

Processing

Question 22

Neurons differ on histological appearance (4 categories)

Answer 22

Unipolar
Bipolar
Pseudo-Unipolar
multipolar

Question 23

Membrane potential ___ the inputs to a neuron

Answer 23

encodes

Question 24

The membrane potential results from a _______ between the inside and outside of the neuron.

Answer 24

Separation of ionic charge

Question 25

______ charge accumulates along the cytoplasmic surface of the membrane due to no diffusible proteins.

Answer 25

Negative

Question 26

_____ charged ions line up along the extracellular surface of the membrane

Answer 26

Positively

Question 27

The membrane potential measures the ____ between ions along the inner and outer surface of the membrane

Answer 27

Force of attraction

Question 28

The membrane potential is proportional to the number of _____ and ______ that accumulate along the two surfaces of the membrane.

Answer 28

- positively | - negatively charged ions

Question 29

The membrane potential is expressed in both its ___ and its ___

Answer 29

- Magnitude | - polarity

Question 30

Polarity is referenced to what side of the membrane potential

Answer 30

-cytosolic

Question 31

The strength of the electric static attraction between ions across the membrane is what ?

Answer 31

Magnitude

Question 32

Why are ion channels needed for a current to pass through the membrane

Answer 32

Because the membrane is impermeable to ions

Question 33

____ channels are controlled by ligand binding to the channel protein to induce the conformational change

Answer 33

Ligand Gating

Question 34

_____ channels require the attachment or detachment of a phosphate group to the channel protein to induce a change in conformation

Answer 34

Phosphorylation

Question 35

_____ channels respond to changes in the electrical potential of the adjacent membrane

Answer 35

Voltage gating

Question 36

_____ channels respond to physical distention of the membrane or change in membrane tension to cause a conformational change

Answer 36

Mechanical forces

Question 37

How do ion specific channels filter ions (2 mechanisms)?

Answer 37

- pore size | - active sites

Question 38

Under normal concentration gradients what ion(s) concentrations are low on the inside but high on the outside of the cell?

Answer 38

Na+ Ca++ CL-

Question 39

Under normal concentration gradients what ion(s) concentrations are high on the inside but low on the outside of the cell?

Answer 39

K+

Question 40

The neuronal membrane is impermeable to what ion(s)?

Answer 40

Na+ Ca++ CL-

Question 41

The neuronal membrane is permeable to what ion(s)?

Answer 41

K+

Question 42

A change in membrane potential is a result of _____ across the neuronal membrane

Answer 42

Ionic currents

Question 43

What gradient is the movement of ions from a high concentration to a low concentration?

Answer 43

Chemical gradient

Question 44

What gradient is described as, like charges repelling; opposite charges attracting

Answer 44

Electrical gradient

Question 45

What two forces cause ions to flow through transmembrane channels

Answer 45

- Chemical Gradients | - Electrical Gradients

Question 46

The strength of an ionic current across a membrane will vary in t direct proportion to ___ and ____

Answer 46

- Strength/magnitude of the gradient | - conductance of the membrane to that ion

Question 47

The flow of ions (quantity per unit time) across the membrane is referred to as what?

Answer 47

I: Ionic "current"

Question 48

What determines the chemical gradient?

Answer 48

(Ci – Co): Concentration difference (inside minus outside)

Question 49

What reflects how readily the ion will pass through channels, relative to the strength of the gradient?

Answer 49

g:membrane “conductance” to a particular ion

Question 50

What expresses the electrical potential that will balance the concentration gradient for an individual ionic species?

Answer 50

The Nernst equation

Question 51

when the membrane potential (Vm) equals the Nernst potential, the system will be in _____

Answer 51

Steady state

Question 52

The electrical potential required to counter-balance the diffusion force arising from the concentration gradient is referred to as _____

Answer 52

(Ei-Eo) The Nernst equilibrium potential or (E)

Question 53

_________tells us that the membrane potential is due to the individual electrochemical gradients, as well as to the membrane conductance to individual ions

Answer 53

The Goldman equation

Question 54

In the Goldman equation, Vm is dependent on what two variables

Answer 54

- Ex: the Nernst equilibrium potential for each ion (K+, Na+, Cl-) - gx: the membrane conductance for each ion