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IMSK Exam 1 > Membrane Physiology: Resting and Reversal Potentials > Flashcards

Membrane Physiology: Resting and Reversal Potentials Flashcards

1
Q

What can disrupt the resting membrane potential of a cell?

A

A change in ion concentrations either inside or outside of a cell

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2
Q

The larger the membrane potential the larger…?

A

The ability to do work

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3
Q

What is used to do work in cells?

A

Difference in ion concentrations

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4
Q

What determines the movement of ions?

A

The sum of differences in the electrical and chemical (concentration) gradient

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5
Q

What is meant that RMP is in equilibrium?

A

The net influx is equal to efflux of ions

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6
Q

Which ion has the greatest affect on the membrane potential?

A

The most permeable one

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7
Q

Is K+ concentration or chemical gradient stronger?

A

Concentration gradient

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8
Q

What is the relative concentration difference of Na+ inside and outside of the cell?

A

x10 more outside the cell

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9
Q

What is the relative concentration difference of K+ inside and outside of the cell?

A

x40 more inside the cell

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10
Q

What is the relative concentration difference of Ca2+ inside and outside of the cell?

A

x25k more outside the cell

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11
Q

What is the relative concentration difference of Cl- inside and outside of the cell?

A

x30 more outside the cell

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12
Q

What does the magnitude of the electrical force depend on?

A

The membrane potential

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13
Q

What does the direction of the electrical force depend on?

A

Ion charge

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14
Q

What is the net force?

A

Sum of chemical + Electrical gradient

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15
Q

How does each ion attempt to change the membrane potential?

A

Each ion tries to move the membrane potential towards its equilibrium potential

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16
Q

Why is the equilibrium potential also called the reversal potential?

A

Because the typical concentration gradient is reversed

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17
Q

What is Cl- Erev?

A

-90 mV

18
Q

What is Na+ Erev?

A

+65 mV

19
Q

What is Ca2+ Erev?

A

+130 mV

20
Q

What is K+ Erev?

A

-95 mV

21
Q

What three terms are synonymous?

A

Nernst Potential, Reversal Potential, Equilibrium Potential

22
Q

What is an equilibrium potential?

A

The membrane potential at which the force of the concentration gradient = electrical gradient

23
Q

What is the Nernst equation?

A

Ex= (60mV/z) log ({X}o/{X}i)

24
Q

What does z stand for in the Nernst equation?

A

Valence number of electrons including the charge

25
Q

What value does a number less than one carry on the log scale?

A

A negative

26
Q

What is the net driving force?

A

Membrane potential-Erev

Current MP-Reversal Potential

27
Q

What is a local potential?

A

A depolarization of the membrane by an influx of Na+ at a specific point on the membrane only

28
Q

What is another name for a local potential?

A

Graded response

29
Q

What happens if another Na+ opens next to the initial channel?

A

It will have an additive affect causing the membrane to become more depolarized

30
Q

What happens to the Na+ that has entered the membrane?

A

It diffuses throughout the inside of the dendrite getting less concentrated as it moves

31
Q

What happens to a local response?

A

It degrades over space and time

32
Q

What is another term for local potential?

A

Synaptic potential

33
Q

Where do local potentials mostly occur?

A

In dendrites and somata of neurons

34
Q

What happens when a sufficient number of depolarizing synaptic potentials occur?

A

The axon initial segment will become depolarized

35
Q

What is a significant depolarization?

A

A depolarization of about 10 mV

36
Q

What is an action potential?

A

A propagated potential that travels along the axon of a neuron

37
Q

What are the properties of Na+ channels?

A

Open quickly to a small depolarization

38
Q

What are the properties of K+ channels?

A

Open slowly to a large membrane depolarization; involved with action potential termination

39
Q

What is the refractory period?

A

The time period in which Na+ channels are inactivated by the inactivation gate to ensure unidirectional propagation of the AP

40
Q

What is the absolute refractory period?

A

When the Na+ gates are inactivated and absolutely no AP can occur

41
Q

What is the relative refractory period?

A

Another AP can be produced only if the stimulus is large enough (while the K+ channels are still closing)

42
Q

What is peripheral neuropathy?

A

Loss of peripheral myelin which slows conductance

IMSK Exam 1 (15 decks)

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