histology nervous system

1-2mos after conception from neurectodermal cells

rER in neurons

• nissl
• golgi
• lipofuscin granules
• nucleus/nucleolus

• void of rER
• voltage dep channels
• origin of AP

folds in axon terminal; gives increased surface area

swelling along length of axon or nerve terminal region; has synaptic vesicles but no well formed synapse; transmitter released to diffuse to target tissue (ANS)

mass of lgly unmyelinated axons and dendrites w/in gray matter of CNS; contains neuronal cell bodies

• lgst glial cell
• make GFAP
• can have cell processes that terminate around capillaries
• foot processes cover non-synaptic surfaces of neurons

• neuronal support and regulation
• reuptake and metabolism of nt
• maintenance of blood-brain barrier and scar formation after CNS trauma

glial cell reactive process

nt

metabolically active (lots rER) w/ numerous cell processes ending in myelination of numerous axons

• produces myelin w/in CNS
• provides myelin sheath to mult axons

• sm cells w/ dense nuclei
• mesodermal origin; from monocytes

phagocytic w/in CNS

epithelium lining ventricular system of CNS

modified ependyma + fenestrated capillaries; extend into ventricles for CSF prod

astrocyte foot process + basement membrane + endothelial cell

• neural crest derivative
• PNS neural glial cell
• myelinates axons in PNS

linear junction at which two sides of Schwann cell come together after ensheathing axon

cytoplasm filled channels in flattened Schwann cell cytoplasm; appear as clefts

nutritive support to inner layers of myelin sheath

surrounds ind axons/myelin

surrounds fascicle of nerve fibers

surrounds groups of nerve fascicles

degenerative changes in axon/myelin distal to site of nerve injury; due to loss of continuity w/ cell body of neuron

displacement of Nissl substance to periphery of cell body

loss of Schwann cells

• 1. nerve transection
• 2. chromatolysis
• 3. prolif and act of Schwann cells distal to site of injury; forms pathways for nerve sprouts

laminn and fibronectin; helps axon grow back (only if myelin tube can be reformed following injury)