Summary CNS histology notes

Nervous tissue

 One of four basic tissues
 Comprised of neurons and neuroglia
o Neurons = basic functional unit
o Neuroglia = provide metabolic and structural support

Neurons

 Properties
o Irritability
o Conductivity
 Consist of
o Nerve cell body (soma)
o Axon
o One or more dendrites
 Multipolar
o Number of processes attached to soma
o Dendrites bring info in
o Single axon neuron
o Most of the neurons in the body
o Motor neurons, sensory, intercommunicating
 Bipolar
o One process in, one process out
o Special sense – eye etc
 Unipolar
o Technically two processes but look like one
o First order sensory neurons
 Receives info from periphery and brins into CNS

Neuroglia of CNS

 Astrocytes
o Maintain chemical environment
o Provide nutrients
o Remove excess neurotransmitter
o Contributed to BBB
 Microglia
o Engulf microorganisms
o Migrate to areas of nerve cell injury
o WBCs cannot pass BBB
 Oligodendrocytes
o Produce myelin sheath around CNS axons
 Ependymal cells
o Line ventricles of brain and central canal of spinal cord
o Form CSF and assist in circulation

Cerebral cortex

 6 layers