Glial cells Flashcards
what are the 2 main pocket lineages of glial cell
microglia and macroglia
what are the four main functions of glial cells
- to surround neurons and provide physical support (hold them in place)
- to supply nutrients and oxygen to neurons (blood brain barrier)
- to insulate one neuron from another and facilitate synaptic communication
- to destroy and remove cell debris and unwanted molecules
what developmental roles do glia have
guiding migration of neurons in early development, and producing molecules that modify the growth of axons and dendrites
what roles do glia have as active participants in synaptic transmission
regulating clearance of neurotransmitter from cleft, releasing factors such as ATP which modulate presynaptic function and sometimes releasing neurotransmitter themselves
Glia are intimately correlated with ________. more advanced organisms -> more _______________.
Glia are intimately correlated with brain evolution. More advanced -> more percentage of brain is made out of glia
when were glial cells first noted and first named
First noted in 1824 and first named in 1856 (virchow)
the discovery of glial cells was credited to who
Rudolf Virchow
The first description of glia was by…
Rene Dutrochet
Otto Deiters claimed the defining feature of glial cells was what?
the lack of axons
who is Pio del Rio-Hortega
a student of Cajal, in 1920 classified the glia into four types: protoplasmic in gray matter, neuroglia in white matter, mesoblastic microglia, and interfascicular glia (what are now oligodendrocytes) – brought him a lot of trouble, he had to move.
what functions of glia cells were proposed by early neuroscientists and proved right
- ability to secrete chemicals (Nageotte)
- association with blood vessels (Golgi)
- morphological plasticity (Cajal)
- ability to electrically insulate (Cajal)
- role in neurotransmitter uptake and termination (Lugaro)
- role in pathology (Virchow).
which neuroglia are found in the peripheral nervous system
satellite cells, schwann cells
what neuroglia are found in the central nervous system
ependymal cells, oligodendrocytes, astrocytes, microglia
which glia originated from neuroectoderm
oligodendrocytes and astrocytes
which glial cells are derived from mesoderm/ yolk sac
microglia
which lineage of human mesenchymal stem cells do glia come from
myeloid
what are macroglia
the major supporting cells and include astrocytes, oligodendrocytes, and ependymal cells.
the endothelial blood brain barrier formation coincides with what?
the onset of vasculogenesis at 6 week of gestation
from 7 weeks gestations what features of the blood-CSF barrier are forms
show tight junctions similar to adult forms in many places (across choroid plexus, pia-arachnoid barrier and CSF-brain barrier)
what are radial glia
a common progenitor, they generate all types of glia. contribute to populating the brain and providing a scaffold for neuronal migration. they differentiate from neural progenitors early in development. somata in the ventricular zone and extending prolongations to the pia.
what does the key stage O2A progenitor give rise to
astrocytes and oligodendrocytes
what transcription factors control oligodendrocyte stepwise differentiation/maturation
notch1 and prox1
what is the precursor cell to oligodendrocytes
NG2 precursors
what major resident glial (precursor) cell population is retained throughout life
NG2 precursors
what cells give rise to schwann cell precursors
neural crest cells
what cells do neural crest cells give rise to
Schwann cell precursors, peripheral sensory and autonomic neurones and satellite cells of the dorsal root ganglia.
what determines whether immature schwann cells differentiate into myelinating or non myelinating cells
early association with large or small diameter axons (respectively)
what is wallarian degeneration
an active process of retrograde degeneration of the distal end of an axon that is a result of a nerve lesion (dedifferentiation of schwann cells is important) - two main causes 1) degenerative diseases affecting nerve cells, and 2) traumatic injury to the peripheral nerves.
what are key factors defining gliogenesis
Sox9 and NFIA
+ shh and notch
what is gliogenesis
the developmental process by which glial cells – astrocytes, oligodendrocytes, Schwann cells, microglia – are generated.
what are the two sites of constant neurogenesis
the lateral subventricular zone (SVZ) and the Dendate Gyrus of the hippocampus
what is the rostral migratory stream (RMS)
the major pathway by which progenitor cells migrate from the subventricular zone (SVZ) to the olfactory bulb (OB)
what protein is involved in astrocyte maturation
S100beta
what macrophage subpopulations are in the brain
microglial cell, meningeal macrophage, dendritic cell, choroid plexus macrophage, perivascular macrophage
what functions do microglial cells have
immunosurveillance, synaptic pruning, neuromodulation, phagocytosis
what are the two primary routes of microglial regulation of brain development
the release of diffusible factors and phagocytosis. phagocytize many products in the brain, including synaptic elements, living cells, dying or dead cells, and axons (remove excess cells (+in neurogenesis in adulthood) and excess synaptic contacts (up to 20yoa))
what two glial cells help regulate synaptic function
astrocytes and microglia
what are the basic characteristics of microglial population distribution
Ramified morphology, tiling the brain parenchyma in a mosaic-like distribution
Biggest differences in morphology between grey (ramified) and white (bipolar) matter
Variable densities in different regions, with each cell covering an average volume of 50000mm3
microglial repertoire of immune sensors and reactants allows…….
……rapid and plastic reactions to disruptions of the brains homeostasis
who was generally considered the father of microglia
Pio del Rio Hortega
what’s the location that perivascular microglial cells are derived showed by Hickey and Kimura in 1988
bone marrow
when did Franz Nissl develop Nissl staining
1880