Neurohistology and Response to Spinal Cord Injury Flashcards
How many layers are there in the cerebral cortex?
6
How many layers are there in the cerebellar cortex?
3
What are the three layers of the cerebellar cortex called?
Outer molecular layer
Purkinje layer
Granule layer
Which cells are found in the granule layer?
Granule cells
Golgi cells
Which cells are found in the molecular layer?
Basket cells
Stellate cells
What are the largest type of cells in the cerebellum?
Purkinje cells
Which glial cells form the blood brain barrier?
Astrocytes
Which glial cells are found in the CNS?
Astrocytes
Oligodendrocytes
Ependymal cells
Microglia
Which glial cells are found in the PNS?
Schwann cells
Satellite cells
What is the role of ependymal cells in the CNS?
Line ventricles and secrete CSF
What is the role of microglia in the CNS?
Immune - phagocytosis and cytokine release
How many axons can an oligodendrocyte myelinate in the CNS?
Many
Name 2 diseases that affect oligodendrocytes
Multiple sclerosis
Leukodystrophies
How many axons can a Schwann cell myelinate in the PNS?
One
Why are some axons not myelinated?
Fast conduction not required i.e. pain, temperature, itch
How do Schwann cells interact with unmyelinated axons?
Envelope axons for protection
Which surrounds a bundle of nerve fibres?
Perineurium
What surround each individual nerve fibre?
Endoneurium
What type of neurons are found in the lateral grey matter of the spinal cord?
Visceral (autonomic) motor neurons
What happens when there is injury to a PNS nerve?
- Schwann cells become reactive and proliferate, secreting growth factors and forming Bands of Bungner
- Macrophage phagocytose debris
- Nerve fibres grow towards and through the bands
What happens when there is injury to a CNS nerve?
Microglia and astrocytes become active
Inflammation occurs
Macrophage begin to remove debris but debris not completely removed
Glial scar formed by reactive astrocytes
What is the process of neuron repair called?
Wallerian Degeneration
Name an inhibitory molecule that reactive astrocytes increase the expression of
Chondroitin sulfate proteoglycans
Name a normal molecular that reactive astrocytes increase expression of
Glial fibrillary acidic protein
Why prevents regrowth of CNS axons?
Myelin debris
Glial scarr
What feature is characteristic of failed axon regeneration and what causes this?
Axons turn away from lesion and form reactive ‘end bulbs’ (swellings of accumulated organelles) at their tips
What is nissl stain used to identify?
Rough endoplasmic reticulum
Polyribosomes
What is the most abundant neuron in the brain?
Granule cells
What are the largest cells in the cerebellum?
Purkinje cells
What is the purpose of astrocytes?
Structural and metabolic support for neurones
Form BBB
What surround individual gangion cells?
Layer of flattened satellite cells
What is the name of the sheath that surrounds individual nerve fibres?
Endoneurium
Where are cell bodies of motor neurons found?
Ventral horn of the spinal cord
What is the name of the repair tissue formed by schwann cells in PNS repair?
Bands of Bungner
What is the boundary between the CNS and PNS called?
Dorsal root entry zone
