Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuro_Week1 > Intro to Neuropath > Flashcards

Intro to Neuropath Flashcards

1
Q

Neurons

1) main function
2) structure
3) replicative or non-replicative in brain?

A

1) transfer information in NS

2) large round, vesicular nucleus with inner nucleolus
dark Nissl substance (RER)
axons have neurofilaments = specialized intermediate fibers + tubules

3) non-replicative in brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe neurofilaments and neurotubules

what are they crosslinked by?

A

neurofilament = specialized cytoskeletal intermediate fibers (10 nm)

neurotubules = intermediate fibers that form tubules (20-26 nm) made of alpha/beta tubulin

crosslinked by tau protein and microtubule assoc proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what happens if axon of neuron damaged?

what is it called?

A

central chromatolysis

Nissl disappears
soma swells
nucleus displaced to side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

neurons are particularly vulnerable to __ and ___ due to high metabolic rate

what changes are seen to reflect necrosis under these conditions?
name?
features?

A

anoxic injuries and low blood glucose

ischemic/red neuron

  • cell shrink
  • eosinophilic as lose basophilic Nissl substance
  • mitochondria condense
  • nuclei become pyknotic (DNA condenss)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Astrocytes

- functions

A
  • clear NT from cleft
  • structural support for blood vessels in BBB
  • maintain ionic equilbirum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

role of astrocytes in brain injury

effective or not?

A

1) scar formation
astrocyte hyperplasia and hyperplasia helps close gaps after neuron debris removed

2) incr synth of GFAP, filament elongation to allows astrocyte to extend processes across lesion
3) creates thick network but NOT effective b/c can’t fill gap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

oligodendroglia
- function

  • regeneration?
A

myelin cells of CNS
nutrition role for deep cortex + basal ganglia

little regeneration in injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

multiple sclerosis mechanism

A

death of oligodendroglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

ependymal cells
- function?

  • regenerative?
A

ciliated cells lining ventricles for CSF movement

inert / limited regeneration from damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what happens if ependymal cells are injured?

seen in what diseases

A

then are permanently damaged

seen in hydrocephalus, bacterial ventriculitis, viral infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

microglia
function?

difference in structure btwn surveillance and activated state?

A

sentinel cells activated by neuron damage, replicate, phag debris

surveillance = long nuclei + short processes
activated = large nuclei + cytoplasm grows into highly branched patterns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

microglia are replenished by…

activated microgllia secrete what?
function of secretion?
A

replenished by blood monocytes and transform into brain macrophage

secrete neuronal trophic factors
assist in recovery
also secrete neurotoxins and cytokins for inflamm/kill neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

significance of RER aka Nissl substance

what happens when axon transected (axotomy)

A

Nissl = stacks of RER and reflect active protein synth

when axon transected, Nissl subtance disaggregates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

basic components of neuronal cytoskleeton

crosslinked by?

A

made of longitudinally arranged neurofilaments (10 nm long) and neurotubules (20-26 nm long)
crosslinked and fastened by tau protein + microtubule assoc proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

function of tau and MAPs?

A

anchor cytoskeleton to membrane + organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

mechanism of alzheimer’s diz at cell level?

A

abnormal paired helical filaments of hyperphosphorylated tau in perikaryon

perikaryon = cell body distinct from nucleus and form forms neurofibrillary tangles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how are silver stains used in histology of CNS

appears what color

A

visualizing axons and dendrites
- silver deposits on cytoskeletal elements dense in neuron

appears black

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

most common silver stain

used to stain what?

A

Bielschowsky stain = shows normal axons and dendrites + neurofibrillary tangles of Alzheimer’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where is GFAP found?

What are Rosenthal fibers?

A

Glial fibrillary acidic protein

  • makes up intermediate filaments of astrocytes
  • component of Rosenthal fibers in diseases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are Rosenthal fibers?

A

Rosenthal fibers = homogenous, eosinophilic, elongated, or glob inclusion in astrocytes from longstanding gliosis, tumors or metabolic disease

21
Q

mutations of GFAP cause what

describe disease

describe course of disease

A

Alexander disease

  • widespread deposits of Rosenthal fibers
  • causes white matter degeneration

slow progressing, fatal in children affecting myelin sheath

22
Q

When and where is myelin first formed?

How long is myelin production

A

starts late in development in periphery

from birth –> many yrs

23
Q

Describe how Schwann cells myelinate PNS axons

A

1) neurons induce Schwann proliferation and migration along axon length
2) Schwann cells elongate and ensheathe neuron
3) axons instruct Schwann to begin wrapping once basal lamina is formed

24
Q

what induces Schwann myelination

A

induced by neurons thru cell-cell interactions and intrinsic gene expression program in Schwann

25
Q

Role of microglia in CNS inflamm and repair

@ rest vs when find injury
secrete what?

A

microglia = first line phagocytic cells

1) @ rest, sample environment to sense foreign materials, toxins, and damage
2) when find injury/invasion –> activated –> nucleus larger and rod with ramified cyto
3) migrate to lesion, replicate, engulf damage
4) secrete cytokine and neurotoxin for neuroinflamm and can kill neurons; also secrete trophic factors for repair

26
Q

what is encircling of degenerating neurons by microglia called

difference from microglial nodules

A

neurophagia

nodules = clustering of microglia aorund foci of necrotic brain tissue

27
Q

what is sarcolemma?
structure?
function?

A

cell membrane of muscle cell
- invaginates deep into cytoplasm of cell –> T-tubules

T tubules allow depol of membrane to rapidly penetrate entire cell

28
Q

what is connected to sarcolemma? how?

A

contractile myofibrils of muscle cells attach to sarcolemma nd ECM via dystrophin

dystrophin connects cytoskeleton to membrane and dystrophin assoc complex (DAC)

29
Q

describe DAC and what it is mad eof

A

made of 5 sarcoglycan proteins ubunits + 2 dystroglycan protein subunits

bound to merosin (part of basement membrane)

30
Q

mutations in dystrophin cause what?

what does it cause?

A

Duchenne and Becker muscular dystrophy

causes ongoing degneration/regen of muscle fibers
causes muscle damage d/t loss of mechanical force of contraction

31
Q

long term changes in DMD and becker’s

A

degeneration faster than reegen so fibers undergo necrosis

muscle replaced by fat and connective tissue –> progressive weakness

32
Q

mutations in gene for DAC can lead to ___

merosin mutations found in __

A

limb girdle dystrophies

some congenital dystrophies

33
Q

describe how type 1 and type 2 fibers distrib in normal muscle and in denervation atrophy

appearance in staining

A

proportion varies based on muscle fxn

BUT ONLY 1 TYPE PER MOTOR UNIT (1 MOTOR NEURON + ALL FIBERS)
(neuron determines type of fiber)

appears as checkerboard under stain

34
Q

what happens to type 1 and type 2 fiber distrib in denervation atrophy

what happens to appearance under stain

A

1) when motor neuron axon cut, muscle fibers lose innerv –> atrophy
2) nearby motor unit axons sprout new growth cones to re-innerv myocytes and incorporate –> new motor unit
3) change in fiber type to assume type of new motor unit (neighbors)
4) loss of checkerboard and creates grouping

35
Q

what is myelin made of?

difference btwn central and peripherl myelin

A

myelin = 70% lipid + 30% proteins
lipid is same = galactocerebroside
proteins differ and usu glycosylated in PNS (not CNS)

36
Q

proteins in myelin of PNS

A

P0
Peripheral myelin protein 22
schwann cell myelin protein
Myelin basic protein

37
Q

proteins in myelin of CNS

A

myelin assoc glycoprotein
myelin oligodendrocyte protein
myelin basic protein

38
Q

Describe Wallerian degeneration

what happens to soma
RER
nucleus
cytoplasm

due to?

A

when axon transected, everything distal degenerates

soma undergoes chromatolysis (swells)
RER disintegrates
nucleus displaces to periphery
cytoplasm –> smooth

due to activation of protein synth to regenerate

39
Q

Wallerian degeneration

How do axons regenerate?

A

Schwann cells distal proliferate and provide growth substrate
regrows 1-3 mm per day

40
Q

Describe segmental demyelination

causes what? effect on conduction velocity?

A

due to dysfunction of Schwann cell or damage to myelin sheath
(nothing wrong withaxon)

loss of myelin from breakdown in few segments –> causes loss of saltatory conduction, decr conduction velocity

schwann cells can make new myelin to repair but demyelin can cause loss of axons and perm damage

41
Q

segmental demyelination

appearance of axon without myelin

A

thin regenerating myelin onion bulbs

42
Q

presence of lewy body (eosinophilic body made of alpha synuclein means)

A

parkinson’s

43
Q

rounded cytoplasmic neuronal inclusion seen in

A

pick’s disease

44
Q

neurofibrillary

A

a

45
Q

myopathy vs denervation

A

myopathy = prox weakness and atrophy
elevated CK
EMG changes

denervation = distal weakness and atrophy
normal CK
diff EMG changes

46
Q

signs of acute denervation

A

randomly distrib small, angular fibers seen

usu type 2 selective

47
Q

signs of chronic denervation

A

type 1 and type 2 proprotion equalizes

48
Q

what are bands of bugner

A

in wallerian degeneration

basal lamina lined endoneurial tubes that ensheath prolif schwann cells

49
Q

clinical signs of nerve regeneration

order

A

1) autonomic
2) sensation
3) motor

Neuro_Week1 (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions