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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
[Action/Graded Potential] Die out over a short distance
Graded Potential
26
[Action/Graded Potential] Large alterations in membrane potential
Action Potential
27
[Action/Graded Potential] Generally very rapid (as brief as 1 to 4 ms) and may repeat at frequencies of several hundred per second
Action Potential
28
Action potentials are generated when voltage-gated sodium and potassium channels are activated at threshold.
Voltage-Gated Ion Channels
29
Steps of Action Potential Mechanism
1. Resting State 2. Depolarization 3. Repolarization 4. Hyperpolarization
30
No ion movement. a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
a. Resting State
31
K+ flows out of the cell. a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
c. Repolarization
32
Na+ flows into the cell. a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
b. Depolarization
33
Some K+ continues to flow out of the cell. a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
d. Hyperpolarization
34
All channels closed. a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
a. Resting State
35
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
d. Hyperpolarization
36
Na+ channels inactivating and K+ channels open. a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
c. Repolarization
37
Na+ channels open (activation gates) a. Resting State b. Depolarization c. Repolarization d. Hyperpolarization
b. Depolarization
38
Graded signals generated in the periphery in response to injury.
Action Potential Inhibition
39
[Action/Graded Potential] Summation: Cannot be summed
Action Potential
40
[Action/Graded Potential] Summation: Can be summed
Graded Potential
41
[Action/Graded Potential] Amplitude: Varies with size of the initiating event
Graded Potential
42
[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.
Action Potential
43
[Action/Graded Potential] Has no threshold
Graded Potential
44
[Action/Graded Potential] Has a threshold usually about 15 mV depolarized relative to the RMP.
Action Potential
45
[Action/Graded Potential] Has no refractory period
Graded Potential
46
[Action/Graded Potential] Has a refractory period
Action Potential
47
[Action/Graded Potential] Conduction: Amplitude decreases with distance
Graded Potential
48
[Action/Graded Potential] Conduction: Is conducted without decrement; the depolarization is amplified to a constant value at each point along the membrane
Action Potential
49
[Action/Graded Potential] Duration: Varies with initiating conditions
Graded Potential
50
[Action/Graded Potential] Duration: Constant for a given cell type under constant conditions
Action Potential
51
[Action/Graded Potential] Magnitude: Only a depolarization
Action Potential
52
[Action/Graded Potential] Magnitude: Can be a depolarization or a hyperpolarization
Graded Potential
53
[Action/Graded Potential] Initiated by environmental stimulus (receptor), by neurotransmitter (synapse) or spontaneously
Graded Potential
54
[Action/Graded Potential] Initiated by a graded potential
Action Potential
55
[Action/Graded Potential] Mechanisms depend on voltage-gated channels
Action Potential
56
[Action/Graded Potential] Mechanism depends on ligand-gated channels or other chemical or physical changes
Graded Potential
57
This toxin blocks voltage-gated Na+ channels. a. Iberiotoxin b. Apamin c. Saxitoxin d. Tetrodotoxin
c. Saxitoxin and d. Tetrotoxin
58
This toxin blocks voltage-gated K+ channels. a. Iberiotoxin b. Apamin c. Stichodactylatoxin d. Tetrodotoxin
b. Apamin and c. Stichodactylatoxin
59
This toxin blocks K+ channels. a. Iberiotoxin b. Apamin c. Saxitoxin d. Tetrodotoxin
a. Iberiotoxin
60
This toxin keeps the Na+ channels from closing. a. Iberiotoxin b. Stichodactylatoxin c. Phoneutriatoxin d. Batrachtoxin
d. Batrachtoxin
61
This toxin slows the closing of Na+ channels. a. Iberiotoxin b. Stichodactylatoxin c. Phoneutriatoxin d. Batrachtoxin
c. Phoneutriatoxin
62
[Absolute/Relative Refractory Period] During the action potential, a second stimulus, no matter how strong, will not produce a second action potential.
Absolute Refractory Period
63
[Absolute/Relative Refractory Period] Coincides roughly with the period after hyperpolarization.
Relative Refractory Period
64
[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.
Absolute Refractory Period
65
[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.
Relative Refractory Period
66
Key in determining the direction of action potential propagation.
Refractory Period
67
Action potentials in neurons are [unidirectional/bidirectional].
unidirectional
68
Action potentials in muscles are [unidirectional/bidirectional].
bidirectional *This is because the action potentials are initiated near the middle of the cells.
69
Action potential propagates along a membrane depends upon these two factors:
1. Fiber diameter 2. Fiber myelination
70
[Contiguous/Saltatory Conduction] The impulse "jumps" from node to node, skipping over the myelinated sections of the axon.
Saltatory Conduction
71
[Contiguous/Saltatory Conduction] Slow conduction velocity - Involves the spread of the action potential along every patch of membrane down the length of the axon.
Contiguous Conduction
72
[Contiguous/Saltatory Conduction] Action potential at one node produces action potential at the next node.
Saltatory Conduction
73
[Contiguous/Saltatory Conduction] Accomplished by local current flow between adjacent membrane patches.
Contiguous Conduction
74
[Contiguous/Saltatory Conduction] Propagates action potential that is 50 times faster.
Saltatory Conduction
75
Examples of anesthetics:
- Procaine (Novacaine) - Lidocaine (Xylocaine)
76
Larger fiber diameter means:
Faster action potential propagation
77
Cells under resting condition
Potential difference
78
Steady transmembrane potential of a cell that is not producing an electrical signal
Resting Membrane Potential (RMP)

PHYSIOL (6 decks)

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