Neuro - Glia# Flashcards
what types of glia are present in the peripheral nervous system
schwann cells
satellite cells
function of satellite cells
surround cell bodies in ganglia
regulate O2/CO2/nutrient/neurotransmitter levels around neurons in ganglia
function of Schwann cells
surround axons in PNS
aid in repair from injuries
what are the types of glia present in the central nervous system
oligodendrocytes
ependymal cells
astrocytes
microglia
function of oligodendrocytes
myelinate CNS axons
provide structural support
function of astrocytes
structural support
maintain BBB
forms scar tissue after injury
recycle neurotransmitters
regulates ion/nutrient/dissolved glass concentrations
function of ependymal cells
assist in the production/circulation and monitoring of cerebrospinal fluid
line the ventricles and central canal
function of microglia
remove cell waste/debris
removes pathogens via phagocytosis
what occurs at 6 weeks of gestation
vasculogenesis at the telencephalic wall
formation of the BBB
what occurs from 7 weeks of gestation onwards
tight junctions present at:
blood-CSF barrier at the choroid plexus
pia-arachnoid barrier
CSF-brain barrier
what is unique about the lineage/structure of radial glial cells
the differentiate earlier than other types of glia from neural progenitors
cell body is located in the ventricular layer
projects all the way into white matter
what type of glial cell can give rise to all cell lineages
radial glia
contribute to populating the brain and provide a scaffold for neurons - neuronal migration
what do O2A progenitors give rise to
astrocytes
oligodendrocytes
how does O2A progenitors lead to the glia the give rise to
the cells acquire their identity as they migrate
depending on the factors they encounter
what do neural crest cells give rise to
schwann precursors
peripheral sensory cells
autonomic neruones
satellite cells
what do immature schwann cells differentiate into and what does it depend on
myelinating or non-myelinating schwann cells
depends on early association with either large or small diameter axons
large - myelinating
small - non-myelinating
comment on the maturation of the astrocyte population
its progressive and mostly postnatal
what are the main macrophages in the brain
microglia
non-parenchymal cells
how do microglia detect and react disturbances to the brain’s homeostasis
equipped with immune sensors/reactants that detect and allow for quick and plastic responses to these disturbances
what are the different types of microglia
systemic sensing
proliferating
phagocytic
neuromodulatory
pruning
surveillant
what gives rise to all macrophage populations
eryhtromyeloid progenitors (EMP’s) derived from yolk sac
what do uncommitted EMP’s express
express specific markers such as:
CD31+ and c-Kit+
how do EMP’s develop
from the macrophage ancestor population - A1 into tje A2 progenitor population
the A2 population commits to microglia
what are the stages in microglial development
EMP–>ameboid microglia–>ramified microglia
outline what happens to ameboid cells in microglial development
during the first 2 weeks of postnatal brain they gain the shape and characteristics of microglia
what is the role of master regulators of macrophage development
drive the specification of EMP’s into immature macrophages
what plays a fundamental role in microglial identity
CSF1
TGFβ
IL34
involved in shaping, maintaining and reinforcing microglial identity
what transcription factors are highly present in microglia
SALL1
SALL3
MEIS3
MAFB
functions of astrocytes - extended
neurogenesis and gliogenesis
neuronal guidance in development
regulation of synaptic maturation and synaptogenesis
acts as microarchitecture for the brain
creation of BBB
synaptic modulation
how do astrocytes respond to pre/postsynaptic stimulation
release Ca2+ stores from their ER
how do astrocytes communicate with neurones
communicate bidirectionally
receive neurotransmitters from neurone
able to their own neurotransmitters/gliotransmitters that change the electrophysiology of the neurone
like short-term plascticity
what do astrocytes clear and provide
active in Glu (glucose) clearance and provision of Gln (glutamine)
in context of the tripartite synapse what does glucose target
kainate receptors
metabotropic glutamate receptors
NMDA receptors
what are another function of the gliotransmitters released by astrocytes
synchronised depolarisation of neurones - results in more EPSP
increased chance and frequency of AMPA-receptor dependant postsynaptic currents
in terms of the tripartite synapse, what does ATP target
P2X receptors
P2Y receptors
A1 receptors
what are the functions of ATP in terms of the tripartite synapse
insertion of AMPA receptors into the postsynaptic terminal
paracrine activity via calcium waves
suppression of synaptic transmissions
what is the suggested method of ATP release
partly dependent on SNARE proteins and Ca2+
and exocytosis releases the ATP
what do the alveus projections of astrocytes in the hippocampal stratum oriens only respond to
changes in Ca2+ concentration only due to cholinergic activity
why do astrocytes in the hippocampal stratum oriens have Glu receptors
they are also capable of detecting glutamatergic activity that originates from the Schaffer collateral brain region
how does the frequency of stimulation from glutamatergic/cholinergic neurons effect calcium concentration
low frequencies - result in potentiated Ca2+ response
high frequencies - results in depressed Ca2+ concentration response
give a localised definition of the BBB
barrier between the intracerebral blood vessels and the brain parenchyma
what is the BBB formed by
tight junctions
astroglial endfeet
where is the BBB not located in the brain
circumventricular organs (CVO’s)
neurohypophysis
pineal gland
subfornical organ
lamina terminalis
