Glia - form and function Flashcards
How many more glia are there than neurones in a human brain?
10x more glia
What do glia offer?
Physical support
Metabolic support
Electrical insulation
Guiding connections
How are glia noticeable?
They cannot be seen by electrophysiological techniques
Morphology
Expression specific markers
Immunohistochemical identification
What are the two divisions of glia?
Macroglia
Microglia
Name the 4 types of macroglia
Schwann cells
Oligodendrocytes
Ependymal cells
Astrocytes
Which two cells form myelin?
Schwann cells
Oligodendrocytes
What are the differences between Schwann cells and oligodendrocytes?
Schwann cells are in the peripheral nervous system
Oligodendrocytes are in the central nervous system
Schwann cells myelinate one axon
Oligodendrocytes myelinate many axons (up to 30)
What does myelination promote?
Regeneration
Can axen regeneration occur in the PNS or CNS?
PNS = yes CNS = no
What allows axon regeneration in the PNS?
Schwann cells and endoneurial tube surrounding the axon encourage growth
What stops axon regeneration in the CNS?
No endoneurial tube
Prevented by signalling in CNS
What is the role of an ependymal cell?
Form the walls of the ventricles in the brain and central canal of the spinal cord
Produce cerebrospinal fluid
What structural adaptations do ependymal cells have?
They are ciliated
Helps circulate the cerebrospinal fluid
Describe an astrocyte
Largest glial cell
Most numerous glial cell
What is the function of an astrocyte?
Neuronal guidance during development
Form architecture of brain and spinal cord