Peripheral Nervous System: Peripheral Nerves

#80 Sciatic Nerve, 2 sections (Cajal)

In the longitudinal section, note the argyrophilic axons, many of which are surrounded by an "unstained" myelin sheath. The neurilemmal sheath (outer layer of Schwann cell cytoplasm) is visible. Find some nodes of Ranvier. What is their role?

In the cross section note the axon (black), which is surrounded in turn by a myelin sheath and its Schwann cell neurilemma (brown). Locate lightly myelinated and unmyelinated fibers. Speed of conduction is related to the diameter (including myelin sheath) of a nerve fiber.

#81 Sciatic Nerve, 2 sections (H&E)

Examine the longitudinal and cross-section and identify the connective tissue of the perineurium. Delicate reticular connective tissue, the endoneurium surrounds individual axons. The epineurium, which is dense irregularly arranged connective tissue, binds many nerve bundles. The epineurium is not present on these sections.

#113 Artery, vein and nerve, (H&E)

Identify the cross section of peripheral nerve. Note that the nervous tissue has shrunk within the perineurium during tissue processing. Only some of the axons within the nerve have been cut in true cross section. What are the cells within the nerve whose nuclei are stained? Find a small nerve elsewhere in the tissue.