Connective tissue in the peripheral nervous system
A nerve contains two types of tissue: (1) nerve fiber, and (2) connective tissue. Dendrites and axons with Schwann cells and myelin sheath are surrounded by connective tissue. A nerve fiber in the peripheral nervous system consists of an axon or long dendrite, myelin sheath (if existent) and their Schwann cells. Peripheral sensory fibers contain long dendrites, but peripheral motor fibers have long axons. Long dendrites of sensory fibers have structural properties as motor axons.
Layers of connective tissue in the nerve
The three layers of connective tissue surround each nerve are:
Epineurium
The epineurium surrounds the nerve trunk (i.e. superficial epineurium). This is considered the outermost layer. The epineurium separates the nerve fascicles, but lies outside the perineurium (i.e. interfascicular epineurium).
Perineurium
Each nerve fascicle is surrounded by the perineurium that includes a group of nerve fibers. The perineurium has a very important role in the protection and support of nerve fibers. This section of connective tissue is an important factor in preventing the passing of large molecules from the epineurium into a fascicle.
Endoneurium
Each nerve fiber is surrounded by the endoneurium. This section is a thin layer of connective tissue. The endoneurium is the tube that places the components of a nerve fiber such as axon, the myelin sheath and Schwann cells into itself. Thus, the endoneurium separates nerve fibers of a fascicle.
References
- fa:بافت همبند در دستگاه عصبی محیطی
- Williams & Warwick. Gray's Anatomy .THIRTY-SEVENTH EDITION.ISBN 0 443 04177 6
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