Peripheral Nerves usually contain axons from

• Motor,
• Sensory, and
• Autonomic neurons
• All mixed in bundles organized into fascicles by CT coverings.

What are the major histological and functional differences between the myelin sheath and the endoneurium?

Examine the cross-section of a large peripheral nerve.

• This section has been prepared with osmium to preserve lipids of myelin and stain this material black. Identify
  • epineurium,
  • perineurium, and
  • endoneurium.
• Identify
  • myelinated and non-myelinated fibers.

The perineurium along with the nature of the capillaries in the endoneurium make up a “blood-nerve barrier” that helps protect the myelin sheathes of peripheral nerves from viral or immunological agents.

Ever wonder about Schwann cells?