Peripheral Nerves usually contain axons from

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

Examine sections of small autonomic ganglia and small peripheral nerves (Fig. 9-28) in loose CT (slide 45) and identify the Schwann (glial) cells.

What are some distinctive features of small peripheral nerves in sections of loose CT?

What other tissue types do small peripheral nerves cut longitudinally resemble slightly?

Examine the cross-section of a large peripheral nerve (Fig. 9-26 and 9-27) in slide 150.

• 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.
• Study electron micrographs of myelinated and non-myelinated nerve fibers (Fig. 9-27) and correlate these with the section on slide 150.

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?