Ionic Basic of Excitation Flashcards

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1
Q

Ions outside of the cell

A

Na, Cl, Mg, HCO3-, Ca

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2
Q

Ions within the cell

A

Proteins (-), PO3-, K+

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3
Q

What are the major anions within the cell?

A

bicarbonate, phosphate, proteins, nucleic acids (cannot leave the cell)

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4
Q

Simplified Nerst equation

A

E=61/z*log(out/in). Z=charge of ion

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5
Q

Postive (inward) current

A

Inward movement of cations, outward movement of anions

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6
Q

Negative (outward) current

A

Outward movement of cations, inward movement of anions

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7
Q

What determines the Vm of a cell?

A

the equilibrium potential of the ion with the highest permeability

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8
Q

What chemical blocks Na-K pump?

A

Ouabain

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9
Q

What happens if the Na-k pump activity decreases?

A

Vm will depolarize

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10
Q

Hyperkalemia

A

Too much K causes dyspnea, arrhythmias, palpitations, chest pain, parestesia, diarrhea

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11
Q

Excitatory PostSynaptic Potential

A

Increases permeability for all cations, results in excitability

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12
Q

Inhibitory PostSynaptic Potential

A

Increased permeability for Cl and K, results in decreased excitability

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13
Q

Glutamate

A

Excitatory nt in CNS (EPSP)

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14
Q

Metabotropic Glutamate Receptor

A

G-protein coupled. Effectors are PLC, adenylyl cyclase, ion channels. Act as autoreceptors to limit glutamate release (presynaptically)

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15
Q

Ionotropic Glutamate Receptor

A

Fast excitatory synaptic responses. Increased conductances (Na, Ca, K)

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16
Q

GABA

A

Major inhibitory nt in CNS (IPSP)

17
Q

Benzodiazepines/barbituates affect on GABA receptors

A

Potentiate GABA(A) response. Used as anti-seizure med

18
Q

Picrotoxin/Penicillin affect on GABA receptors

A

Blocks GABA (a) channel. Leads to seizures

19
Q

GABA (B) receptor

A

G-protein coupled. Slow response

20
Q

M-gate of voltage-gated Na channel

A

Rapid opening, Na rushes in when open. Is depolarization

21
Q

H-gate of voltage-gated Na channel

A

Slow inactivation. Na flow stops when closed

22
Q

What voltage-gated channel is delayed in opening?

A

K. Is sequential to Na influx

23
Q

Absolute Refractory Period

A

No action potential no matter how strong the stimulus

24
Q

Relative Refractory Period

A

AP only results from supra-threshold stimuli

25
Q

Passive conduction

A

Passive spread of local response. Travels short distances

26
Q

Active conduction

A

All or non response. Spreads along the entire axon

27
Q

Factors that affect AP conduction velocity

A

Axon diameter. Saltatory conduction (myelination)