Glial Diversity Flashcards
test 1 content
what are the types of oligodendrocytes and what do they do?
myelinating oligodendrocytes: insluate and nourish, about 30 myelin sheets per oligodendrocyte
non-myelinating oligodendrocytes: nourish short axons
what are some characteristics of oligodendrocytes?
make up 30% of all glia, continue oligodendrogenesis throughout life from oligodendrocyte precursor cells and myelin remodeling, lead to alterations in neuroplasticity by wiring together cells that fire together
what do protoplasmic astrocytes do?
reside in gray matter and BBB, part of the tripartite synapse, provide structural support and clear glutamate/ions from synpase, synaptogenesis, pruning, fill space, each have a distinct domain they support and do not overlap with others
what are some characteristics of astrocytes?
astrocytes are the most abundant type of glia in the CNS as seen by GFAP immunolabeling, there are two types: protoplasmic and fibrous astrocytes
what do fibrous astrocytes do?
reside in white matter, end feet attach to capillaries in the BBB, provide structural support and nourishment to axons
what are radial glia and what are the two types?
glia that guide cell migration in the cortex and elsewhere, bergmann and muller glia are the two subtypes
what do bergmann glia do?
a type of radial glia in the cerebellum that promote granule cell migration, have microglia-like functions such as synaptic pruning and gliosis (scar tissue formation from glia in brain)
what do muller glia do?
a type of radial glia in the retina that can dedifferentiate into neural progenitor cells, have microglia-like functions and conduct light
what are ependymal cells and what are the 5 types?
ependymal cells are cells that line the ventricular system and the 5 types are: ependymocytes, tanycytes, marginal glia, perivascular glia, and velate glia
what do ependymocytes do?
act as a barrier to the ventricular surface, their cilia help circulate CSF and their microvilli reabsorb CSF, chroroid plexus cells are a subtype of ependymocytes that make CSF from blood plasma
what do tanycytes do?
line the border of the third ventricle and regulate blood -> CSF border and the CSF -> brain transport of molecules, permit bidirectional movement of fluids between the ventricles and the blood stream, adjacent to capillaries
what do marginal glia do?
form a barrier between brain parenchyma and meninges, act as the first line of defense even though astrocytes get all the credit
what do perivascular glia do?
part of the BBB, cover capillaries in the brain
what do velate glia do?
chemical and structural barrier in glomeruli
what kind of diseases can result from BBB failure?
alzheimers, parkinsons, and huntingtons disease
what kind of diseases can result from protein accumulation?
alzheimers and alexanders disease
what kind of diseases can result from abnormal pruning?
fragile X
what kind of diseases can result from abnormal development?
rett syndrome, fragile X, and alexander disease
what kind of diseases can result from CSF abnormality?
hydrocephaly
what two diseases of those discussed are not heritable?
guillain barre syndrome: autoimmune response against myelin triggered by virus/bacteria, causes demyelination in the PNS
multiple sclerosis: autoimmune disease that attacks the myelin sheet stabilizing proteins which leads to demyelination that slows or stops action potentials and eventually leads to neuronal death
quadripartite vs tripartite synapse
quadripartite: astrocytes, microglia, and pre/post synaptic cell
tripartite: astrocytes, pre/post synaptic cell
what are some characteristics of microglia?
make up 15% of glia, have both baseline and activated states, triggered in alzheimers disease, stroke and ALS, neuroinflammation leads to neurodegeneration
baseline vs activated state of microglia
baseline: support neurogenesis and synapses, phagocytosis, synaptic pruning/stripping
activated: activated when an invader is encountered, present antigens to lymphocytes, produce proinflammatory mediators, similar to macrophages
what are the two types of schwann cells and what do they do?
myelinating: conductance, support regeneration by allowing the myelin sheath to remain so that a new neuron can fill the space
non-myelinating: covers small axons, supports, nourishes, phagocytosis of dead cells
what are the two diseases caused by mutations on schwann cells?
charcot-marie-tooth: myelin protein gene mutation, demyelination/remyelination in PNS
guillain-barre: autoimmune response against myelin in triggered by virus/bacteria, demyelination in PNS
how are satellite cells similar to other cells?
like schwann cells: they cover axons plus they cover sensory/autonomic ganglia
like astrocytes: support, nourish, and remove glutamate from synapses
like microglia: activated upon nerve injury, mount and inflammatory response and alter sensory neuronal activity
oligodendrocytes to schwann cells are like microglia to which cell?
satellite cells
oligodendrocytes selectively surround axons, whereas astrocytes selectively support cell bodies, true or false?
false, astrocytes also support axons
what are the glia in the CNS vs the PNS?
CNS: oligodendrocytes, astrocytes, radial glia, ependymal cells, and microglia
PNS: schwann cells and satellite cells
