lect 12 pt 6

What does the endoneurium surround?

The endoneurium wraps around an individual nerve fiber and its associated Schwann cells.

Does the endoneurium surround only the axon?

No, it surrounds the fiber along with its associated Schwann cells and myelin sheath when present.

What are the three connective tissue layers of a peripheral nerve?

Epineurium surrounds the entire nerve, perineurium surrounds each fascicle, and endoneurium surrounds each individual nerve fiber.

What is a nerve fascicle?

A nerve fascicle is a bundle of individual nerve fibers within a peripheral nerve.

What structures are found inside a nerve fascicle?

Individual nerve fibers, each surrounded by endoneurium.

What is the difference between a nerve and a nerve fascicle?

A nerve contains multiple fascicles, while each fascicle contains multiple individual nerve fibers.

What are the two appearances of myelinated fibers that may be seen in histological cross-sections?

Some show a visible, layered myelin sheath around the axon, while others show the axon surrounded by an apparently empty space.

What is the myelin sheath made of that makes it vulnerable to tissue-processing solvents?

It consists of many layers of cell membrane, which contains a phospholipid bilayer rich in lipids.

What is the relationship between Schwann cells and myelin in a peripheral nerve?

Schwann cells wrap their cell membranes around axons to form myelin sheaths when the axons are myelinated.

What does the endoneurium surround when an axon is myelinated?

It surrounds the nerve fiber, including the axon and its associated Schwann cell and myelin sheath.

What is another term for support cells of nervous tissue?

Glial cells or neuroglial cells.

What does fiber mean in nervous tissue terminology?

A long cellular process that may be an axon or dendrite when its identity cannot be determined.

What is the CNS term for a bundle of nerve fibers?

A tract.

What is the PNS term for a bundle of nerve fibers?

A nerve.

What is the CNS term for a cluster of neuronal cell bodies?

A nucleus.

What is the PNS term for a cluster of neuronal cell bodies?

A ganglion.

Which CNS support cell forms myelin around axons?

The oligodendrocyte.

Which PNS support cell forms myelin around axons?

The Schwann cell, also called a neurolemmocyte.