Cellular component of the CNS Flashcards
What are the cellular components of the CNS?
Nerve cells
Microglia
Glial cells
Supporting structures
Glial cells are derived from what?
Neuroectoderm
What are the two broad functions of the glial cells
- Supporting system for neurones
- primary role in reaction to injury/fluid balance/inflammation
What are the three types of glial cells?
Astrocytes
Oligodendrocytes
Ependymal cells
What is the shape of astrocytes?
Star shaped with multipolar synaptic processes
Which glial cell provides a fixed 3D grid within which other CNS cells are supported?
Astrocytes
What are the 3 roles of astrocytes?
- Homeostasis
- Maintain BBB (with endothelial cells)
- Repair and scar formation
What is also known as the astrocyte response?
Gliosis
What happens in gliosis?
Nucleus enlarges
becomes vesicular
nucleolus is prominent
What is glial fibrosis?
In old lesions the nuclei become small and dark and lie in a dense net of processes
What do oligodendrocytes produce?
Myelin in the CNS
What are oligodendrocytes very sensitive to?
Oxidative change ( as they have a high concentration of iron)
Damage to oligodendrocytes (and potentially apoptosis) is a feature of what type of disorder?
demyelinating
Damage to myelin sheath can result in which 2 things?
- Conduction reduced
2. Axons exposed to injury
What do ependymal cells line?
The ventricular system
Local proliferation of sub-ependymal astrocytes to produce small irregularities on the ventricular surface is termed…
ependymal granulations
Microglia are derived from which cells?
Mesoderm-derived cells
Where do microglia originate in?
Bone marrow (haematopoietic origin)
What is the role of microglia?
Immune monitoring
Antigen presentation
Serves as a fixed macrophage system
What are the two mediators of microglia?
M2-anti-inflammatory, phagocytic, more acute
M1- Pro-inflammatory, more chronic
What are the 3 supporting structures of the CNS
Connective tissue
Meninges
Blood vessels
