Glial cells Flashcards Preview

2911 Brain and Behaviour > Glial cells > Flashcards

Flashcards in Glial cells Deck (9)
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1

What are the different types of glial cells?

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

2

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)

3

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

4

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.

5

What is the function of ependymal cells?

- line the ventricles and central canal of the spine

6

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

7

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.

8

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.

9

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)
Evidence:
- 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)