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Flashcards in Glial cells Deck (9)
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What are the different types of glial cells?

Oligodendrocytes in CNS (and Schwanna cells in PNS)
Ependymal cells


What is the function of astrocytes?

- most abundant glial cell.
Important for :
-breakdown of neurotransmitters
- growth factors (chemicals involved in growth and repair of damaged cells).
- structural support (anchor neurons to help get a regular blood supply).
- transport nutrients into neuron and remove waste products
- protects BBB (helps to push endothelial cells together)


What is the function of oligodendrocytes?

- provides myelin sheath (insulation of neurons) --> only in brain.
- in peripheral NS Schwann cells provide myelin sheath
- in MS --> immune system attacks oligodendrocytes


What is the function of microglia?

- main immune defence in the brain
- when there is an injury or infection, microglia multiply and migrate to the site --> engulfs microorganism or infected neurons.


What is the function of ependymal cells?

- line the ventricles and central canal of the spine


How do neurons and glial cells differ?

- glial cells do not cause APs (rapid electrical signals) like neurons
- glia surround and ensheath neuronal cell bodies, axons and synapses throughout nervous system.
- neurons communicate via synapses


How do astrocytes communicate with each other?

- communicate via waves of calcium ions, propagating information over large distances.
- stimulation of one astrocyte can cause a calcium response in neighbouring astrocytes (indicating a distinct network of astrocytes in a mosaic pattern).
- these cells are linked by structures in their cell bodies called gap junctions.


How do glia and neurons communicate?

- can make contact with, and ensheath thousands of synapses formed between neurons
- synapses have an astrocytic projection that envelops the synapse.
Tripartite synapse:
- astrocytes respond to many of same NT as neurons. When a neuron releases Ca- based signalling, this cascade in astrocytes and also release various active substances such as LTP.
- the synaptic localisation of astrocytes means they are ideally placed to respond to and monitor synaptic activity.
- astrocytes can release proteins, which control synapse formation, regulate presynaptic function and modulate response of postsynaptic neuron and NT.


How do we know that abnormal glia activity is linked to neurodegenerative diseases?

- most neurodegenerative disorders are associated with abnormal glial activity
- can have excitotoxic effects (e.g. too much glutamate in the synapse)
- increase glial activity in Parkinson's Disease and schizophrenia
- increased cytokines in neurodegenerative disorders
- studies that show rats who get an infn early in life have a hyperactive immune response (hyperactive glial activity and cytokines)--> affects memory (indicating possible brain damage)