Schwann Cell Anatomy

1. Review textbook sections on neuron structure and classification of neurons and neuroglia.

2. As a review activity, label figures 25.1 and 25.2.

3. Complete Parts A and B of Laboratory Report 25.

4. Obtain a prepared microscope slide of a spinal cord smear. Using low-power magnification, search the slide and locate the relatively large, deeply stained cell bodies of motor neurons (multipolar neurons).

5. Observe a single motor neuron, using highpower magnification, and note the following features:

cell body nucleus nucleolus chromatophilic substance (Nissl bodies)

neurofibrils (threadlike structures extending into the nerve fibers)

nerve fibers (axon and dendrites)

Compare the slide to the neuron model and to figure 25.3. You also may note small, darkly stained nuclei of neuroglial cells around the motor neuron.

6. Sketch and label a single motor neuron in the space provided in Part C of the laboratory report.

7. Obtain a prepared microscope slide of a dorsal root ganglion. Search the slide and locate a cluster of sensory neuron cell bodies. You also may note bundles of nerve fibers passing among groups of neuron cell bodies (fig. 25.4).

8. Sketch and label a single sensory neuron cell body in the space provided in Part C of the laboratory report.

9. Obtain a prepared microscope slide of neuroglial cells. Search the slide and locate some darkly stained astrocytes with numerous long, slender processes (fig. 25.5).

10. Sketch a single neuroglial cell in the space provided in Part C of the laboratory report.

11. Obtain a prepared microscope slide of a nerve. Locate the cross section of the nerve, and note the many round nerve fibers inside. Nerve fiber is a

Figure 25.1 Label this diagram of a motor neuron.

Figure 25.1 Label this diagram of a motor neuron.

Schwann Cell Anatomy
Figure 25.2 Label the features of the myelinated nerve fiber.
Multipolar Neuron Spinal Cord Smear
Figure 25.3 Micrograph of a multipolar neuron and neuroglia from a spinal cord smear (100x micrograph enlarged to 600x).
Nerve Fiber Schwann

-Nerve fiber (axon)

Nerve Fiber SchwannHuman Spine Diagram With Labels

general name for processes (either dendrites or axon) of the neuron. Also note the dense layer of connective tissue (perineurium) that encircles the nerve fibers and holds them together in a bundle. The individual nerve fibers are surrounded by a layer of more delicate connective tissue (endoneurium) (fig. 25.6).

12. Using high-power magnification, observe a single nerve fiber and note the following features:

central axon myelin around the axon (actually, most of the myelin may have been dissolved and lost during the slide preparation)

neurilemma

13. Sketch and label a single nerve fiber with Schwann cell (cross section) in the space provided in Part D of the laboratory report.

Figure 25.6 Cross section of a bundle of neurons within a nerve (400x).

Figure 25.6 Cross section of a bundle of neurons within a nerve (400x).

Myelinated Nerve Fiber 100x

Connective tissue (perineurium)

Connective tissue (endoneurium)

Axon (nerve fiber)

Myelin of Schwann cell

Neurilemma of Schwann cell

Connective tissue (perineurium)

Connective tissue (endoneurium)

Axon (nerve fiber)

Myelin of Schwann cell

Neurilemma of Schwann cell

Figure 25.7 Longitudinal section of a nerve (250x micrograph enlarged to 2,000x).

Figure 25.7 Longitudinal section of a nerve (250x micrograph enlarged to 2,000x).

Microscope Slide Neurilemma

Node of Ranvier Axon (nerve fiber)

Myelin of Schwann cell

Neurilemma of Schwann cell

Node of Ranvier Axon (nerve fiber)

Myelin of Schwann cell

Neurilemma of Schwann cell

14. Locate the longitudinal section of the nerve on the slide (fig. 25.7). Note the following:

central axons myelin sheaths of Schwann cells neurilemmal sheaths of Schwann cells nodes of Ranvier

15. Sketch and label a single nerve fiber with Schwann cell (longitudinal section) in the space provided in Part D of the laboratory report.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook


Responses

  • mebrahtu
    Are schwann cells multipolar?
    5 years ago
  • LISA
    What are schwann cells in anatomy?
    3 years ago
  • azzurra
    How to sketch a single nerve fiber with schwann cell?
    8 months ago
  • BISRAT
    Can you see nuerilemma ina single nerve fiber cross section?
    2 days ago

Post a comment