Anatomy and Cell Biology 3309 Lecture Notes - Lecture 14: Endoneurium, Perineurium, Epineurium
19 Aug 2019
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Acb 3309 lecture 14 (nervous tissue and its organization) Can have myelinated and unmyelinated neurons, within 1 nerve. Endoneurium, perineurium, and epineurium connective tissue coverings of the spinal nerves. Endoneurium covers each individual axon: endoneurium is a thin lct, almost looks like cell boundary bc its very thin. Is present whether myelin is there or not. Is formed by myoepithelial cells: blood vessels are outside of the perineurium. These cells form tight junctions w one another, to keep the blood vessels out of the ns. So, they help protect the ns/peripheral nerves: don"t want bad stuff from blood getting into ns. A couple fascicles come together to form a spinal nerve. Epineurium covers around spinal nerve and space b/w fascicles: dict, provides strength and stability to the peripheral nerve. In cns, myelination took place bc of oligodendrocytes. But in pns, myelination takes place bc of schwann cells. During development, had an axon closely associated w a schwann cell.
