Nervous Tissue
Background
Nervous tissue, which occurs in the brain, spinal cord, and nerves, contains neurons
and neuroglial cells. The neurons are the basic structural and functional units of the
nervous system involved in decision-making processes, detecting stimuli, and
conducting messages. The neuroglial cells perform various supportive and protective
functions for neurons.
Materials Needed
Textbook
Use the web site: http://wps.aw.com/bc_marieb_ehap_8/25/6525/1670654.cw/index.html to view prepared
microscope slides of the following:
spinal cord smear
dorsal root ganglion
nerve (ls)
 Nerve (cs)
Neuron model
Purpose of the Exercise
Review the characteristics of nervous tissue and observe neurons, neuroglial cells,
and various features of the nerves.
Procedure
1. Label figures 25.1 and 25.2.
2. View the online 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).
3. Observe a single motor neuron, using high-power magnification, and note (label) the following features:
cell body, nucleus, nucleolus, chromatophilic substance (Nissl bodies), neurofibrils, dendrites,
axon.
4. Sketch and label a single motor neuron (similar to one in notes) in the space provided in Part A.
5. View online 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.
6. Sketch and label two single sensory (afferent) neurons (a bipolar neuron) cell body in the space
provided in Part A.
8. Locate online a prepared microscope slide of a nerve (ls). Locate the cross section of the nerve and
note the many round nerve fibers inside. 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)
9. Using high-power magnification observe a single nerve fiber and note the following
features: central axon, myelin around the axon, node of ranvier.
10. Sketch and label a single nerve fiber with Schwann cell (cross section) in the
space provided in Part B.
11. Locate the nerve (cs) on high power. Note the following: axons, myelin, Schwann cell nucleus
12. Sketch and label a single nerve fiber with Schwann cell (longitudinal section) in
the space provided in Part B.
Figure 25.1 Label this diagram of a motor neuron.
Figure 25.2 Label the features of the myelinated axon (nerve fiber).
4
Part A
1. Sketch and label a single motor neuron.
2. Sketch and label a single sensory neuron cell body.(bipolar)
Part B
1. Sketch and label a single nerve fiber with Schwann cell (cs).
2. Sketch and label a single nerve fiber with Schwann cell (ls).
Part C
Match the terms in column B with the descriptions in column A. Place the letter of
your choice in the space provided.
Column A
___ 1. Sheath of Schwann cell containing cytoplasm
and nucleus that encloses myelin
Column B
a. Astrocyte
b. Axon
___ 2. Corresponds to rough endoplasmic reticulum in
other cells
c. Nissl body
___ 3. Network of fine threads within nerve fiber
d. Collateral
___ 4. A membranous sheath of insulation around
an axon.
e. Dendrite
f. Myelin
___ 5. Neuron process with many branches that
conduct an impulse toward the cell body
g. Neurilemma
___ 6. Branch of an axon
h. Neurofibrils
___ 7. Star-shaped neuroglial cell between neurons
and blood vessels (blood brain barrier)
___ 8. Nerve fiber that conducts an impulse away from the cell body
Part D
Match the terms in column B with the descriptions in column A. Place the letter of
your choice in the space provided.
Column A
___ 1. Transmits impulse from sensory to motor neuron
within the central nervous system
Column B
a. Effector
b. Ependymal
___ 2. Transmits impulse out of the brain or spinal cord
to effectors
___ 3. Transmits impulse into brain or spinal cord from
receptors
c. Ganglion
d. Interneuron
e. Microglia
___ 4. Myelin-forming neuroglial cell in brain and spinal
cord
f. Motor neuron
___ 5. Phagocytic neuroglial cell
g. Oligodendrocyte
___ 6. Structure capable of responding to motor impulse
h. Sensory neuron
___ 7. Specialized mass of neuron cell bodies outside the
brain or spinal cord
___ 8. Covers the inside spaces of the ventricles