Glial cells Flashcards Preview

2911 Brain and Behaviour > Glial cells > Flashcards

Flashcards in Glial cells Deck (9)
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1
Q

What are the different types of glial cells?

A

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

2
Q

What is the function of astrocytes?

A
  • 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
Q

What is the function of oligodendrocytes?

A
  • provides myelin sheath (insulation of neurons) –> only in brain.
  • in peripheral NS Schwann cells provide myelin sheath
  • in MS –> immune system attacks oligodendrocytes
4
Q

What is the function of microglia?

A
  • 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
Q

What is the function of ependymal cells?

A
  • line the ventricles and central canal of the spine
6
Q

How do neurons and glial cells differ?

A
  • 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
Q

How do astrocytes communicate with each other?

A
  • 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
Q

How do glia and neurons communicate?

A
  • 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
Q

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

A
  • 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)