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PHYSIOL > MEMBRANE PHYSIOLOGY > Flashcards

MEMBRANE PHYSIOLOGY Flashcards

1
Q
  • Sodium ions (Na+)
  • Chloride ions (Cl-)
A

Extracellular fluid (ECF)

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2
Q
  • Potassium ions (K+)
  • Ionized non-penetrating molecules (phosphate compounds and proteins w/ negatively charged side chains)
A

Intracellular fluid (ICF)

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3
Q

[Insulators/Conductors]

Materials that have a high electrical resistance reduce current flow.

A

Inslulators

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4
Q

[Insulators/Conductors]

Low resistance and allow rapid current flow.

A

Conductors

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5
Q

[Insulators/Conductors]

Lipids contain very few charged groups.

A

Insulators

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6
Q

[Insulators/Conductors]

Water contains dissolved ions.

A

Conductors

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7
Q

[Insulators/Conductors]

ECF and ICF can carry currents.

A

Conductors

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8
Q

____________ ____________ is a good region of electrical resistance.

A

Plasma membrane

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9
Q

[TRUE/FALSE]

All cells at rest have a potential difference across their plasma membrane.

A

TRUE

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10
Q

Inside of the cell is [negatively/positively] charged with respect to the outside.

A

negatively

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11
Q

Extracellular fluid (ECF) exists because of a tiny excess of [negative/positive] charge inside the cell and an excess of [negative/positive] ions outside.

A

negative; positive

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12
Q

ICF has an excess of a negative charge value of ______ mV.

A

-70

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13
Q

________ is the voltage reference point.

A

ECF

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14
Q

Neurons have a resting membrane potential of approximately ______ to ______ mV.

A

-40 to -90

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15
Q

Negative charge inside repels K+ from moving out of the cell. This is due to the _____________ ______________.

A

Electrical Potential

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16
Q

The concentration gradient favors the diffusion of Na+ inside and K+ outside. This is due to the _____________ ______________.

A

Chemical Potential

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17
Q

This equation describes the equilibrium potential for any ion. The electrical potential is necessary to balance a given ionic concentration gradient across a membrane.

A

Nernst Equation

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18
Q

Essentially an expanded version of the Nernst equation. Takes into account individual permeabilities.

A

Goldman-Hogkin-Katz (GHK) Equation

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19
Q

Property of the membrane in which channels give a cell the ability to produce electrical signals.

A

Excitability

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20
Q

[Action/Graded Potential]

Potential change of variable amplitude and duration that is conducted decrementally and has no threshold or refractory period.

A

Graded Potential

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21
Q

[Action/Graded Potential]

Magnitude varies directly with the magnitude of the stimulus.

A

Graded Potential

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22
Q

[Action/Graded Potential]

Spread decrementally by local current flow.

A

Graded Potential

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23
Q

[Action/Graded Potential]

Brief all-or-none depolarization of the membrane, which reverses polarity in neurons, has a threshold and refractory period and is conducted without decrement over long distances.

A

Action Potential

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24
Q

[Action/Graded Potential]

Occurs in an active area of the membrane.

A

Graded Potential

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25
Q

[Action/Graded Potential]

Die out over a short distance

A

Graded Potential

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26
Q

[Action/Graded Potential]

Large alterations in membrane potential

A

Action Potential

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27
Q

[Action/Graded Potential]

Generally very rapid (as brief as 1 to 4 ms) and may repeat at frequencies of several hundred per second

A

Action Potential

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28
Q

Action potentials are generated when voltage-gated sodium and potassium channels are activated at threshold.

A

Voltage-Gated Ion Channels

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29
Q

Steps of Action Potential Mechanism

A
  1. Resting State
  2. Depolarization
  3. Repolarization
  4. Hyperpolarization
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30
Q

No ion movement.

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

a. Resting State

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31
Q

K+ flows out of the cell.

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

c. Repolarization

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32
Q

Na+ flows into the cell.

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

b. Depolarization

33
Q

Some K+ continues to flow out of the cell.

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

d. Hyperpolarization

34
Q

All channels closed.

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

a. Resting State

35
Q

Some K+ channels remain open, and Na+ channels reset (activation gates close and inactivation gates open).

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

d. Hyperpolarization

36
Q

Na+ channels inactivating and K+ channels open.

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

c. Repolarization

37
Q

Na+ channels open (activation gates)

a. Resting State
b. Depolarization
c. Repolarization
d. Hyperpolarization

A

b. Depolarization

38
Q

Graded signals generated in the periphery in response to injury.

A

Action Potential Inhibition

39
Q

[Action/Graded Potential]

Summation: Cannot be summed

A

Action Potential

40
Q

[Action/Graded Potential]

Summation: Can be summed

A

Graded Potential

41
Q

[Action/Graded Potential]

Amplitude: Varies with size of the initiating event

A

Graded Potential

42
Q

[Action/Graded Potential]

Amplitude: All or none. Once the membrane is depolarized at threshold, the amplitude is independent of the size of the initiating event.

A

Action Potential

43
Q

[Action/Graded Potential]

Has no threshold

A

Graded Potential

44
Q

[Action/Graded Potential]

Has a threshold usually about 15 mV depolarized relative to the RMP.

A

Action Potential

45
Q

[Action/Graded Potential]

Has no refractory period

A

Graded Potential

46
Q

[Action/Graded Potential]

Has a refractory period

A

Action Potential

47
Q

[Action/Graded Potential]

Conduction: Amplitude decreases with distance

A

Graded Potential

48
Q

[Action/Graded Potential]

Conduction: Is conducted without decrement; the depolarization is amplified to a constant value at each point along the membrane

A

Action Potential

49
Q

[Action/Graded Potential]

Duration: Varies with initiating conditions

A

Graded Potential

50
Q

[Action/Graded Potential]

Duration: Constant for a given cell type under constant conditions

A

Action Potential

51
Q

[Action/Graded Potential]

Magnitude: Only a depolarization

A

Action Potential

52
Q

[Action/Graded Potential]

Magnitude: Can be a depolarization or a hyperpolarization

A

Graded Potential

53
Q

[Action/Graded Potential]

Initiated by environmental stimulus (receptor), by neurotransmitter (synapse) or spontaneously

A

Graded Potential

54
Q

[Action/Graded Potential]

Initiated by a graded potential

A

Action Potential

55
Q

[Action/Graded Potential]

Mechanisms depend on voltage-gated channels

A

Action Potential

56
Q

[Action/Graded Potential]

Mechanism depends on ligand-gated channels or other chemical or physical changes

A

Graded Potential

57
Q

This toxin blocks voltage-gated Na+ channels.

a. Iberiotoxin
b. Apamin
c. Saxitoxin
d. Tetrodotoxin

A

c. Saxitoxin and d. Tetrotoxin

58
Q

This toxin blocks voltage-gated K+ channels.

a. Iberiotoxin
b. Apamin
c. Stichodactylatoxin
d. Tetrodotoxin

A

b. Apamin and c. Stichodactylatoxin

59
Q

This toxin blocks K+ channels.

a. Iberiotoxin
b. Apamin
c. Saxitoxin
d. Tetrodotoxin

A

a. Iberiotoxin

60
Q

This toxin keeps the Na+ channels from closing.

a. Iberiotoxin
b. Stichodactylatoxin
c. Phoneutriatoxin
d. Batrachtoxin

A

d. Batrachtoxin

61
Q

This toxin slows the closing of Na+ channels.

a. Iberiotoxin
b. Stichodactylatoxin
c. Phoneutriatoxin
d. Batrachtoxin

A

c. Phoneutriatoxin

62
Q

[Absolute/Relative Refractory Period]

During the action potential, a second stimulus, no matter how strong, will not produce a second action potential.

A

Absolute Refractory Period

63
Q

[Absolute/Relative Refractory Period]

Coincides roughly with the period after hyperpolarization.

A

Relative Refractory Period

64
Q

[Absolute/Relative Refractory Period]

Occurs during the period when the voltage-gated Na+ channels are either already open or have proceeded to the inactivated state during the first action potential.

A

Absolute Refractory Period

65
Q

[Absolute/Relative Refractory Period]

The interval following the absolute refractory period during which a second action potential can be produced, but only if the stimulus strength is considerably greater than usual.

A

Relative Refractory Period

66
Q

Key in determining the direction of action potential propagation.

A

Refractory Period

67
Q

Action potentials in neurons are [unidirectional/bidirectional].

A

unidirectional

68
Q

Action potentials in muscles are [unidirectional/bidirectional].

A

bidirectional

*This is because the action potentials are initiated near the middle of the cells.

69
Q

Action potential propagates along a membrane depends upon these two factors:

A
  1. Fiber diameter
  2. Fiber myelination
70
Q

[Contiguous/Saltatory Conduction]

The impulse “jumps” from node to node, skipping over the myelinated sections of the axon.

A

Saltatory Conduction

71
Q

[Contiguous/Saltatory Conduction]

Slow conduction velocity
- Involves the spread of the action potential along every patch of membrane down the length of the axon.

A

Contiguous Conduction

72
Q

[Contiguous/Saltatory Conduction]

Action potential at one node produces action potential at the next node.

A

Saltatory Conduction

73
Q

[Contiguous/Saltatory Conduction]

Accomplished by local current flow between adjacent membrane patches.

A

Contiguous Conduction

74
Q

[Contiguous/Saltatory Conduction]

Propagates action potential that is 50 times faster.

A

Saltatory Conduction

75
Q

Examples of anesthetics:

A
  • Procaine (Novacaine)
  • Lidocaine (Xylocaine)
76
Q

Larger fiber diameter means:

A

Faster action potential propagation

77
Q

Cells under resting condition

A

Potential difference

78
Q

Steady transmembrane potential of a cell that is not producing an electrical signal

A

Resting Membrane Potential (RMP)

PHYSIOL (6 decks)

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