Glia Flashcards
Glia are also called ??? and are specialised cells found in close association with neurons.
neuroglia
TRUE or FALSE: There are ~10 times more glia than neurons.
TRUE
Glia support neuronal function. They provide neurons with ??? support and maintain appropriate microenvironment essential for neuronal function.
structural
Glia are critical for neuronal signalling through roles in ???, neurotransmitter balance, potassium (K+) buffering etc
myelination
??? (glia type) can be found in both white and grey matter
astrocytes
what is the most abundant type of glia?
astrocytes
Astrocytes play crucial roles in neurodevelopment and in maintaining the cellular environment to avoid disruptions to neuronal ???
signalling
Astrocytes remove potassium from the ??? fluid to ensure appropriate concentration of K+ is maintained on the inside vs outside of cell
extracellular fluid (ECF)
inwardly rectifying potassium channels 4.1 (Kir4.1 channels) on ??? membranes take K+ from the ECF and internalise it
astrocyte
astrocytes are connected to each other by ??? junctions
gap junctions
Kir4.1 (potassium channel) is enriched at astrocytic endfeet where it co-localizes with ??? cannels. These channels facilitate bidirectional water flow in all cells and tissues and is highly expressed in astrocytes.
aquaporin 4
??? channels have been implicated as a key determinant of glymphatic function. The glymphatic system is a brain-wide network of perivascular pathways along which CSF enters the brain and interstitial solutes are cleared.
aquaporin 4 (AQP4)
Glymphatic exchange is driven by ??? pulsation, active primarily during sleep, contributes to the clearance of interstitial amyloid-β, tau, and other solutes such as lactate, and inflammatory cytokines.
arterial
Astrocytes sit very close to glutamatergic and GABAergic synapses (i.e. they are perisynaptically located) and have glutamate and GABA transporters on their membranes. They clear glutamate and GABA from the ???using these transporters and metabolise them
synaptic cleft
Through a process called reactive ???, astrocytes respond to varying amounts of brain injury
astrogliosis
scar-forming ??? occurs at the lesion site to isolate tissue damage. Astrocytes upregulate glial fibrillary acidic protein (GFAP), hypertrophy, proliferate, overlap their cellular processes to form a dense astrocytic border that encloses a lesion core of non-neural cells.
astrogliosis
TRUE or FALSE: Endothelial cells of capillaries only form tight junctions in the presence of astrocytes
TRUE
radial glia is a type of ??? that acts as a “highway” to help guide newborn neurons to their correct location in the cerebral cortex
astrocyte
In the CNS, the myelin forming glia are oligodendrocytes. In the PNS, the myelin forming glia are ??? cells.
Schwann
Oligodendrocytes are derived from the neuro-ectoderm. Schwann cells are derived from the ???
neural crest
Oligodendrocytes are primarily located in WHITE or GREY matter?
white matter
When nerves are injured in the PNS, SCHWANN CELLS or OLIGODENDROCYTES actively secrete molecules which promote axon growth and therefore nerve repair?
Schwann cells
In the CNS in response to nerve/ axon injury, SCHWANN CELLS or OLIGODENDROCYTES release molecules that inhibit axon growth/repair.
oligodendrocytes
In Multiple Sclerosis, antibodies are produced which attack and lead to the death of ??? and subsequent axonal dysfunction
oligodendrocytes
Guillain Barre Syndrome: a demyelinating disease of PNS, ??? are attacked by auto-immune response. After a period of disease progression, the condition stabilises and then spontaneously improves (with proliferation of the ??? and reconstitution of myelin sheath)
Schwann cells
??? are essentially the macrophages of the brain, they are considered the brains “immune cell” and provide constant surveillance of local microenvironment
Microglia
??? are produced in the embryonic yolk sac and migrate into brain during development. Once in brain they have ability to proliferate
Microglia
In injury, ??? migrate to site and are involved in phagocytosis to remove dead/damaged tissue. They can release neurotoxic chemicals during this process which can trigger inflammatory response in the brain = further damage.
microglia
Faults with synaptic pruning by ??? during brain development can contribute to development of disorders such as schizophrenia and autism
Microglia
Amoeboid or ramified (?) microglia are associated with the developing CNS
Amoeboid
Ramified or reactive (?) microglia are present in abundance in the brain parenchyma- constitute ~10–20% of total population of glial cells in the adult. Have many processes which provide constant surveillance of the local micro-environment.
Ramified Microglia
In response to injury or pathogen invasion, quiescent ramified microglia proliferate and transform into active ‘brain macrophages’ otherwise known as ???
reactive microglia
TRUE or FALSE: reactive microglia can produce reactive oxygen species (ROS) and pro-inflammatory cytokines (e.g. interleukin 1b, interleukin 6, tumor necrosis factor a) which can cause secondary neuronal dysfunction/damage.
TRUE
??? are derived from the neuro-ectoderm, providing the lining of ventricles in the brain and the central canal in the spinal cord
ependymal cells
which type of glia is involved with formation/production of CSF?
ependymal cells
Ependymal cells synthesise proteins modulating neurogenesis and/or stem cell self-renewal, such as ???
noggin
