Neurophysiology Flashcards

1
Q

peripheral neuropathy

A

pain and dysesthesia

  • loss of sensation or reflex;weakness
  • fasciculations and paresthesia
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2
Q

mononeuropathy

A

involve isolated neurons

-trauma or pressure

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3
Q

radiculopathy

A

damage to nerve roots

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4
Q

polyneuropathy

A

metabolites, toxins, demyelinateing disease, chronic infections

can affect axon, myelin, or synapse

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5
Q

diabetic neuropathy

A

hyperglycemia is trigger

  • pro-oxidative and pro-inflammatory
  • PNS cells more susceptible
  • predominantly axonal damage
  • variable demyelination
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6
Q

resting membrane potential

A

-65

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7
Q

synaptic potential

A

slow, graded, local

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8
Q

action potential

A

brief, actively propagated and traveling

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9
Q

equilibrium

A

current of ion moving in and out of cell is equal

–determined by charge and concentration

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10
Q

establishment of RMP

A

inward Na
outward K

-closer to K - because it has greater permeability

maintained bt Na/K ATPase pump

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11
Q

capacitor

A

lipid bilayer

-stores charge on opposite sides

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12
Q

resistor

A

ion channels

-allow certain amount of ions to flow

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13
Q

conductance

A

flow of ion across membrane

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14
Q

resistance

A

opposite of conductance

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15
Q

depolarization

A

due to inward Na current

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16
Q

hyperpolarization

A

due to outward K current

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17
Q

voltage-gated Na channels

A

open - membrane depolarization
inactivation - closed and will not reopen
deinactivated or resting - after membrane repolarized, return to conformation that allows them to opened in response to depolarization

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18
Q

voltage gated K channels

A

open - slowly, response to depolarization
-do not inactivate
resting - after membrane repolarized

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19
Q

steps in AP

A

depolarization

  • rising phase
  • falling phase
  • undershoot
  • resting
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20
Q

temporal summation

A

multiple signal over time may reinforce eachother

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21
Q

spatial summation

A

multiples signals that are physically close may influence eachother

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22
Q

time constant

A

how long to reach final voltage

  • depends on number of channels
  • many open channels, lower time constant
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23
Q

length constant

A

distance required for current to decline

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24
Q

neuromuscular junction

A

unmyelinated at axon

  • release of acetylcholine
  • muscle fiber - ligand gated ion channels
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25
Q

muscle atrophy

A

due to loss of trophic effect on muscle

26
Q

fibrillation or fasciculation

A

neurotransmitter loss from damaged axon or schwann cells

27
Q

peripheral nerve disease

A

motor - muscle atrophy

autonomic nerves - sweating lost, dry, cracked skin

28
Q

loss of efferent autonomics

A

lose sweating

dry cracked skin

29
Q

loss of afferent autonomics

A

changes in sensation, pain

30
Q

internodal segment

A

myelin between two nodes

31
Q

saltatory conduction

A

AP - travels along internodal parts of axon

-speeds signal speed

32
Q

nerve conduction studies

A

myelin damage - slow conduction

axon damage - failure of propagation, ectopic propagation, decreased SNAP amplitude

33
Q

PNS regeneration

A

schwann cells dedifferentiate

  • macrophage phagocytose
  • anterograde degeneration (wallerian)
  • retrograde signaling induces reorganization of soma (chromatolysis)
  • regeneration - neurite sprouts guided by schwann cells until connection mae
  • schwann cells redifferentiate
34
Q

fibrous astrocytes

A

white matter

-long and thin processes

35
Q

protoplasmic astrocytes

A

gray matter

-short and frilly processes

36
Q

astrocytes

A

control brain ECF

  • store all glycogen in brain
  • limit K accumulation
37
Q

membrane potential in brain

A

lower

-85

38
Q

primary brain injury

A

at time of injury

-axonal injury, vascular injury, CN injury, contusion, laceration

39
Q

secondary brain injury

A

within 12-24 hours

-swelling, infection, increased ICP, hypoxic injury

40
Q

edema

A

glial cells - uptake of K, followed by Cl and water - swelling

41
Q

generalized edema

A

increased total ICP

-increase arterial pressure

42
Q

focal edema

A

displaces nearby structure

43
Q

Sx of edema

A

headache, vomiting, altered consciousness, focal neuro problems

44
Q

Tx of edema

A

hyperventilation - alkalosis induces vasoconstriction

osmolytes - mannitol

45
Q

scar formation

A

astrocyte and microglia

-reactive gliosis - scar or plaque formation

46
Q

neurotransmitter release

A

Ca induced

47
Q

termination of signal

A

uptake or degradation

48
Q

uptake to presynaptic cell

A

serotonin, dopamine, NE

49
Q

neuropeptides

A

fast axonal transport

50
Q

amines and amino acids

A

made in presynpatic cytoplasm

51
Q

excitotoxicity

A

excessive accumulation of neurotransmitter in brain ECF

52
Q

glutamate

A

inhibits Na/K ATPase

53
Q

excitation

A

fast - ligand-gated ion channels

slow - GPCRs

54
Q

EPSP

A

closer to threshold

55
Q

IPSP

A

moves away from threshold

56
Q

potentiation

A

repeated APs

-more neurotransmitter with each AP

57
Q

depression

A

high frequency AP - depletion of vesicles

low frequency - intracellular Ca - induce phosphatase

58
Q

memory

A

synapses physical site of memory storage

59
Q

working memory

A

fleeting changes

60
Q

long-term memory

A

sensitivity of synapse to past activity influences long-term effectiveness

61
Q

long-term potentiation

A

increase amplitude of EPSPs

62
Q

long term depression

A

decrease amplitude of EPSPs