neuroglia Flashcards

1
Q

what are two main points about neuroglia

A

are not passive

just as important of not more so than neurons

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2
Q

why are neuroglia so important

A

many neurodegenerative diseases involve neurons and neuroglia and when they function incorrectly it can cause a number of problems

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3
Q

what are the three basic types of neuroglia

A

astrocytes
microglia
oligodendrocytes/ schwann cells

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4
Q

what are the two different terms for astrocytes

A

in grey matter- protoplasmic

white matter-fibrous

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5
Q

what do astrocytes contain

A

gap junctions(connexins) between them and specialised bundles of intermediate filaments

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6
Q

why do astrocytes have gap junctions

A

so they can propagate their own signals

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7
Q

what do specialised intermediate bundles within astroocytes contain

A

specialised proteins which can act as markers for these cells

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8
Q

what is the main function of astrocytes

A

separate nerve cells and oligodendrocytes so maintain integrity of NS

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9
Q

describe astrocytes ‘end feet’

A

cover most of free space on neuronal synapses and dendrites, capillaries and oligodendroyctes and they form cuffs around nodes of ranvier

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10
Q

what are three examples of molecules that astrocytes act as a buffer against

A

extracellular K
other ions
pH fluctuations

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11
Q

how do astrocytes affect the CNS

A

detoxify and provide homeostasis

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12
Q

what do astrocytes produce

A

cytokines and growth factors which can effect proliferations and survival of neurons
cell dhesion molecules which guide neuronal development

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13
Q

in the embryo what do astrocytes develop from

A

radial glial which span the brain parenchyma forming the framework for neural migration

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14
Q

describe astrocytes in adults

A

radial glial develop to form progenitors of astrocytes

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15
Q

what is the blood brain barrier

A

responsible for inducing and maintaining the tight junctions in the endothelial cells that form that barrier

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16
Q

where are microglia locates

A

in white and grey matter

17
Q

what is the structure of microglia

A

have rod like somas and numerous processes do not seem to form networks like astrocytes

18
Q

when are micrgolia activated

A

in diseases- proliferate and migrate to injury site

here they change morphology anf have thicket processes and larger cell bodies

19
Q

what are the three functions of microphages

A

express MHC-1 and MHC-2
produce cytokines
act as macrophages

20
Q

what are MHC 1 and MHC 2

A

antigen presenting cells to T cells

21
Q

where are oligodendrocytes locates

A

CNs
white matter- cerebellar tracts
corpus collosum
also found in grey matter

22
Q

what is the funciton of oligodendrocytes

A

can meylinate several axons

23
Q

where are schwann cells located

24
Q

what are 4 functions of schwann cells

A

myelination of neurons
separate neurons and isolate
in injury act as phagocytes
and secrete

25
what are three secretions of schwann cells
laminin fibroconectin collagen all components of basal lamina and extracellular matrix
26
what is the main major function for both schwann cells and oligodendrocytes
produce myelin for saltatory conduction
27
when does myelination occur
late embryonic gestation and post-natal with CNS caudal to rostral and after PNS
28
describe the coverage of myelin
not continuous nodes of ranvier sheath divided into segments called internodes
29
what is myelin
specialised extension of cell membrane of myelinationg cells
30
describe the number of axons myelinated in oligodendrocytes and schwann cells
20-30 internodes | one schwann cell wraps around one axon
31
what bundles the nyelinated nerve in PNS
perinieum
32
what is a mesaxon process
forms a cup around the point of contact whose lips advance around axon until they meet one then passes underneath other to become inner leaf which roates to form multiple layers
33
what is multiple sclorosis
immune mediated demyelinating disease
34
what is charcot marie tooth
demyelation of nerves of PNS