Exercise 15 - Histology of Nervous Tissue
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Exercise 15 – Histology of Nervous Tissue
Name
Sedrick Nari
Instructions and Review Sheet
Once you have completed the below activities, please answer the questions on the following pages and
submit this completed document to me in Canvas. You must have a copy of the lab manual to complete
this exercise.
Please read the entire exercise in your lab manual. Pay particular attention to the figures
– the practical portion of the exam will use images and figures taken from the lab manual and
handouts like this one.
In this lab, the main classroom materials consist of prepared slides and microscopes, as well a model of
neuron. Fig. 15.2 depicts a neuron - you can use that image in place of the 3D classroom model -
make
sure you can identify the various parts of a neuron labeled here
. The rest of the lab involves looking at
prepared slides and making illustrations - you can do this in your lab manual but I will not be collecting
the drawings - please just complete the entire Review Sheet and turn that in.
Note that I may use these
supplemental images as part of the Exam 4 practical.
Activity 1
involves looking at a prepared slide of a neuron, such as the one shown here. Identify the
structures that are visible here.
Where you are asked to sketch a myelinated nerve fiber, you can us Image 15.4 or this supplemental
figure. Note that this image has a very clear demonstration of the “myeline sheath gap”- this gap
between Schwann cells is also known as the “Node of Ranvier”.
For
Activity 2
you can refer to the images supplied in the manual.
Activity 3
asks you to draw a peripheral nerve in cross-section. You can use the supplied image (Fig. 15.8)
or the image below to identify the relevant structures.
Cells of the Nervous System
1. The basic functional unit of the nervous system is the neuron. What is the major function of this cell
type?
To produce and transmit nerve impulses
2. Name four types of neuroglia in the CNS, and list a function for each of these cells. (You will need to
consult your textbook of lecture materials for this.)
Types
Functions
a.
Ependymal cells
b.
Astrocytes
c.
Oligodendrocytes
d.
Microglia
a.
produces and regulates cerebrospinal fluid
b.
helps maintain structure of the nervous tissue
c.
forms and maintains the myelin sheath
d.
primary immune defense in the CNS
Name the PNS neuroglial cell that forms myelin:
Schwann cells
Name the PNS neuroglial cell that surrounds neuron cell bodies in ganglia:
Satellite cells
3. Match each description with a term from the key.
Key:
a. afferent neuron
e. interneuron
i. nuclei
b. central nervous system
f. neuroglia
j. peripheral nervous system
c. efferent neuron
g. neurotransmitters
k. synaptic clef
d. ganglion
h. nerve
l. tract
B
1. the brain and spinal cord collectively
F
2. specialized supporting cells in the nervous system
K
3. junction or point of close contact between neurons
H
4. a bundle of axons inside the CNS
E
5. neuron serving as part of the conduction pathway between sensory and motor neurons
J
6. ganglia and spinal and cranial nerves
I
7. collection of nerve cell bodies found outside the CNS
C
8. neuron that conducts impulses away from the CNS to muscles and glands
A
9. neuron that conducts impulses toward the CNS from the body periphery
G
10. chemicals released by neurons that stimulate or inhibit other neurons or effectors
Neuron Anatomy
4. Match the following anatomical terms (column B) with the appropriate description or function
(column A).
Column A
Column B
C
1. region of the cell body from which the axon originates
B
2. secretes neurotransmitters
F, D
3. receptive regions of a neuron (2 terms)
G
4. insulates the nerve fibers
D
5. site of the nucleus and most important metabolic area
H
6. involved in the transport of substances within the neuron
E
7. essentially rough endoplasmic reticulum, important metabolically
A
8. impulse generator and transmitter
a. axon
b. axon terminal
c. axon hillock
d. cell body
e. chromatophilic substance
f. dendrite
g. myelin sheath
h. neurofibril
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5. Match the labels in this illustration of a multipolar neuron with the appropriate terms
E
axon
B
nucleus
H
axon terminals
F
myelin sheath
C
nucleolus
G
myelin sheath gaps (nodes of Ranvier)
A
dendrites
D
chromatophilic substance
6. What substance is found in synaptic vesicles of the axon terminal?
Neurotransmitters
7. What anatomical characteristic determines whether a particular neuron is classified as unipolar,
bipolar, or multipolar?
Identify which neuron is unipolar, bipolar, and
multipolar.
A.
Unipolar
B.
Bipolar
C.
Multipolar
8. Correctly identify the sensory (afferent) neuron, interneuron, and motor (efferent) neuron in the
figure below.
a.
sensory neuron
b.
interneuron
c.
motor neuron
Which of these neuron types is/are unipolar?
Sensory neurons
Which is/are most likely multipolar?
Interneurons and motor neurons
9. Describe how the Schwann cells form the myelin sheath encasing the nerve fibers.
Schwann cells wrap themselves around the axon this forms a tight coil material which forms the myelin
sheath.
Structure of a Nerve
10. What is a nerve?
A nerve is a bundle of fibers that receives and sends messages between the body and the brain.
11. State the location of each of the following connective tissue coverings.
endoneurium:
the innermost connective tissue layer that surrounds the axons.
perineurium:
a connective tissue layer that surrounds fascicles.
epineurium:
outermost connective tissue layer that surrounds the entire nerve.
12. What is the function of the connective tissue wrappings found in a nerve?
To protect and insulate the nerve.
13. Define
mixed nerve
.
A nerve that contains both sensory and motor neurons.
14. Lebel all indicated parts of the illustrated nerve.
a.
axon
b.
myelin sheath
c.
endoneurium
d.
perineurium
e.
fascicle
f.
epineurium
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