Flashcards in Glial cells Deck (9)
What are the different types of glial cells?
Oligodendrocytes in CNS (and Schwanna cells in PNS)
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.
- 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.