Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MSK Final > Membrane Potentials > Flashcards

Membrane Potentials Flashcards

1
Q

Have gates controlled by change in membrane potential

A

voltage gated channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

have gates controlled by the binding of a ligand such as a neurotransmitter

A

ligand-gated channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the potential difference generated across a membrane when an ion diffuses down its concentration gradient

A

diffusion potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

the magnitude of a diffusion potential depends on what?

A

the size of the concentration gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the driving force of diffusion potential?

A

concentration gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is diffusion potential measured in?

A

millivolts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Movement of an ion across the membrane is determined by what?

A

both by the concentration gradient and by the electrical potential difference across the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

estimates the equilibrium potential for a given ion

A

the nernst equation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the approximate concentration of Na+ in the ECF?

A

140 mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the approximate concentration of Na+ in the ICF?

A

14 mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the approximate concentration of K+ in the ECF?

A

4 mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the approximate concentration of K+ in the ICF?

A

120 mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the equilibrium potential for Na+?

A

+65 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the equilibrium potential for K+?

A

-95 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

the driving force for net diffusion of ions must account for what?

A

both the concentration gradient and the electrical potential across the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do you calculate the net driving force?

A

[membrane potential (mV)]- [equilibrium potential for a given ion (mV)]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If the driving force is negative [membrane potential is more negative than the equilibrium potential for a given ion] what will happen?

A

cation will enter the cell, anion will leave the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

if the driving force is positive, what will happen?

A

cation will leave the cell, anion will enter the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

the activation gate of the Na+ channel in nerve is opened by what?

A

depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens to the inactivation gate of the Na+ channel in depolarization?

A

it is closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

At rest, the nerve membrane is far more permeable to…?

A

K+ than to Na+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Makes the membrane potential less negative (the cell interior becomes less negative aka more positive)

A

Depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

makes the membrane potential more negative

A

hyperpolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

the flow of positive charge into the cell

A

inward current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

inward current causes what?

A

depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

the flow of positive charge out of the cell

A

outward current

27
Q

outward current causes what?

A

hyperpolarization

28
Q

membrane potential at which the action potential is inevitable

A

threshold

29
Q

portion of the action potential where the membrane is positive

A

overshoot

30
Q

portion of the action potential where the membrane is actually more negative than at rest of hyperpolarized

A

undershoot

31
Q

period during which another action potential cannot be elicited

A

absolute refractory period

32
Q

period during which another action potential can only be generated with a stronger stimulus because the threshold has raised

A

relative refractory period

33
Q

at rest, the activation gate is?

A

closed

34
Q

at rest the inactivation gate is?

A

open

35
Q

at the peak of the action potential, the slow inactivation gate will?

A

close

36
Q

when the membrane potential has repolarized back to its resting level, the activation gate will be? and the inactivation gate will be?

A

the activation gate will be closed and the inactivation gate will be open

37
Q

What affect does depolarization have on K+ channels?

A

slowly opens K+ channels and increases K+ conductance

38
Q

What is repolarization caused from?

A

an outward K+ current

39
Q

When the serum/blood K+ concentration increases, what happens to the K+ equilibrium potential and the resting membrane potential?

A

they become less negative

40
Q

What happens to the inactivation gates on Na+ channels with hyperkalemia?

A

they are closed

41
Q

a reduction in the serum/blood potassium concentration will do what to the cell membrane?

A

hyperpolarize it

42
Q

the process that occurs when the cell membrane is held at a depolarized level such that the threshold potential is passed without firing an action potential

A

accommodation

43
Q

if depolarization occurs slowly enough, the Na+ channels do what?

A

The Na+ channels close and remain closed

44
Q

In accommodation, The upstroke of the AP will not be able to occur because?

A

there are not enough Na+ channels available to carry inward current

45
Q

What effect does lidocaine have on action potentials?

A

Lidocaine will block voltage-gated Na+ channels and therefore the inward current of Na+ and the upstroke of the AP will not occur

46
Q

the speed at which action potentials are conducted along a nerve or muscle fiber

A

conduction velocity

47
Q

What two factors affect time constant?

A

membrane resistance and membrane capacitance

48
Q

How does a high membrane resistance (Rm) affect time constant?

A

it will increase it; current does not readily flow 1

49
Q

the ability of the cell membrane to store charge

A

membrane capacitance

50
Q

what affect does a high membrane capacitance (Cm) have on the time constant?

A

it will increase it because injected current must first discharge the membrane capacitor before it can depolarize it

51
Q

What are the cable properties?

A

Time constant and length constant

52
Q

The length constant indicates what?

A

how far a depolarizing current will spread along a nerve

53
Q

When will the length constant be longest?

A

when the diameter of the nerve is large (Ri is low and Rm is high)

54
Q

What effect does increased nerve diameter have on internal resistance?

A

decreases internal resistance

55
Q

What effect does myelination have on membrane resistance?

A

increases it

56
Q

What effect does myelination have on nerve capacitance?

A

decreases it

57
Q

Periodic breaks at regular intervals along the length of the myelin sheath covering an axon

A

Nodes of Ranvier

58
Q

Is the membrane resistance high or low at nodes of ranvier?

A

low

59
Q

the AP will seem to leap along the axon from node to node

A

saltatory conduction

60
Q

Where are action potentials generated in myelinated nerves?

A

at the nodes of ranvier

61
Q

Loss of the myelin sheath around nerves causes what?

A

a decrease in membrane resistance

62
Q

What effect does a decrease in membrane resistance have on an AP?

A

current “leaks out” across the membrane during conduction of local currents

63
Q

What are the signs and symptoms of MS?

A

weakness of the LEs, numbness, paresthesia, blurred vision, and pain with eye movements

MSK Final (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions