If you disable the "Active Content" in your browser you may not
be able to view the animations or videos supplied in this lab.
If prompted you should "Allow Blocked Content".
Access each of the listed
documents above and print them off. When you submit your
lab report you will need to compile all of the documents
listed above, stapled together in the order listed in
the table above. Sketches must be performed free hand
(not traced or copy and pasted). Sketches must be
performed using the printed links as given above. You
are not allowed to perform the sketches on blank sheets
of paper or lined sheets of paper. Sketches performed
without using these forms above will not be accepted.
You can use the MS WORD links to access the questions,
tables and charts in order to input your values or
answers electronically and then print them off when
finished to include with your lab report. Alternatively
you can print the questions, tables and charts forms out
and input your values or answers by hand. The PDF file
format will not allow you to input values or answers
electronically. Please collate and order the pages in
your lab report in the order they are listed in the
table above. The cover page is only available using the
PDF file format.
The spinal cord is an association and
communication center. It plays a major role in spinal
reflex activity and provides neural pathways to and from
higher nervous centers. The spinal cord extends from the
foramen magnum of the skull to the first or second
lumbar vertebra. It is cushioned and protected by
meninges. The dura mater, pia mater, and arachnoid
meningeal coverings extend to the sacral level.
The meninges extend well beyond the
end of the spinal cord and provides an excellent site
for removing cerebrospinal fluid for analysis (for
suspected bacterial or viral infections of the spinal
cord) without endangering the spinal cord. This
procedure, called a lumbar tap, is usually performed in
the lumbar region. Anesthesia for childbirth is normally
administered lower in the lumbar region.
Thirty-one pairs of spinal nerves
arise form the spinal cord to serve the body area at
their approximate level of emergence. The cord is about
the size of a thumb in circumference for most of its
length, but there are enlargements in the cervical and
lumbar areas where the nerves serving the upper and
lower limbs emerge.
The spinal nerves emerging from the
inferior end of the cord must travel through the
vertebral canal for some distance
before exiting at the appropriate location. This
collection of spinal nerves traversing the inferior end
of the vertebral canal is called the cauda equina
because of its similarity to a horse’s tail (the Latin
translation of cauda equina).
SKETCH
1 **Using
images in this lab and your textbook, sketch a
lateral view of the spinal cord and label the following:
Cauda equina, Cervical spinal nerves,
Thoracic spinal nerves,
Lumbar spinal nerves,
Sacral spinal nerves
FIGURE 2.1 Spinal Cord Lateral View
FIGURE 2.2 Spinal Nerves
Human
Cadaver Spinal Cord
Dissection
Use the link below to access a
video in which the spinal cord on a human cadaver is
diseccted and explained.
In cross section, the gray matter of
the spinal cord looks like a butterfly or the letter H.
Figure 2.3 and Figure 2.4 can be used to sketch the
cross sectional view of the spinal cord. The two
posterior projections are called the posterior or dorsal
horns. The two anterior projections are the anterior or
ventral horns. Gray matter surrounds the central canal
of the cord, which contains cerebrospinal fluid.
Neurons with specific
functions can be located in the gray matter. The
posterior horns, for instance, contain association
neurons and sensory axons that enter the cord from the
body periphery via the dorsal root. The cell bodies of
these sensory neurons are found in enlarged areas of the
dorsal root called the dorsal root ganglion. The
anterior horns contain cell bodies of motor neurons of
the voluntary system, which send their axons out via the
ventral root of the cord to enter the spinal nerve. The
spinal nerves are formed from the fusion of the dorsal
and ventral roots. The lateral horns contain cell bodies
of motor neurons of the automatic nervous system
(sympathetic division). Their axons also leave the cord
via the ventral roots, along with those of the motor
neurons of the anterior horns.
FIGURE 2.3 Microscopic Spinal Cord Cross Section
SKETCH 2 **Using
images in this lab and your textbook, sketch a spinal
cord cross section and label the following:
White Matter, Gray Matter, Posterior
horns, Anterior horns, Central canal
The white matter is composed of
myelinated fibers. Some fibers run to higher centers,
some travel from the brain to the spinal cord, and some
conduct impulses from one side of the cord to the other.
The white matter on each side of the
spinal cord can be divided into three primary regions:
the posterior funiculi, lateral funiculi, and anterior
funiculi. Each funiculus contains a number of fiber
tracts composed of axons. Tracts conducting sensory
impulses to the brain are called ascending tracts.
Tracts carrying impulses from the brain to the skeletal
muscles are descending tracts.
Because it serves as the transmission
pathway between the brain and the body periphery, the
spinal cord is an extremely important organ. The spinal
cord is highly vulnerable to traumatic injuries, such as
might occur in an automobile accident. When the cord is
severely traumatized, both motor and sensory functions
are lost in body areas normally served by that region
and lower regions of the spinal cord. Injury to certain
spinal cord areas may even result in a permanent
paralysis of both legs (paraplegia) or of all four limbs
(quadriplegia).
FIGURE 2.4 Spinal Cord Cross Section 3D
FIGURE 2.5 Microscopic Spinal Cord Cross
Section
FIGURE 2.6 Microscopic
Spinal Cord Cross Section
SKETCH
3 **Using
images in this lab and your textbook, sketch a 3
dimensional cross section of the spinal cord
and label the following:
Dorsal root, Dorsal root
ganglion, Ventral root, Spinal nerve,
Dura mater,
Arachnoid, Pia mater, White columns, Gray matter
FIGURE 2.7 Microscopic Spinal Cord Cross
Section
Click the play button to
view the movie to the right on the anatomy of the spinal
cord.
An alternative view
for this animation is given below:
SKETCH
4 **Using
images in this lab and your textbook, sketch and label a view of the spinal
cord that indicates the tract names that follow:
Fasciculus gracilis, Fasciculus cuneatus, Posterior
spinocerebellar, Anterior spinocerebellar,
Lateral spinothalmic, Anterior spinothalmic, Lateral
corticospinal, Ventral corticospinal, Rubrospinal,
Tectospinal, Vestibulospinal
Since each tract is represented on
both sides of the cord, for clarity you can label the
motor tracts on the right side of the diagram and the
sensory tracts on the left side of the diagram.
Color ascending tracts
red and descending tracts blue.
FIGURE 2.8 Spinal Cord
FIGURE 2.9 Ascending and Descending Tracts of the
Spinal Cord
Click the play button to
view the movie to the right on the Spinal Cord Tract
anatomy.
An alternative view
for this animation is given below:
As spinal
cord sensory nerve fibers of different sizes and functions enter
the spinal cord they are
sorted into nerve tracts. Some tracts serve to link different
segments of the spinal cord, while others ascend to higher centers
in the brain. The white matter of the cord consists of ascending
and descending tracts embedded in Neuroglia. Functions of these tracts
can be summarized in the TABLE FOR SPINAL CORD TRACT FUNCTION.
TABLE
1 **Using
information gathered from your text book and the internet,
enter the functional importance of each of the spinal cord
tracts in Table for Spinal Cord Tract Function.
As you work, try
to be aware of how the naming of the tracts is related to their
anatomical distribution.
You can access the Table by clicking on the link given
below.
The Table for Spinal Cord Tract Function is
available by printing out the Sketches Tables Charts
Form
TABLE OF SPINAL
CORD TRACT FUNCTION
Lateral spinothalamic
Pain and temperature
Anterior spinothalmic
Pain and temperature
Fasciculus gracile
Touch, pressure and
conscious muscle joint sense
Fasciculus cuneate
Touch, pressure and
conscious muscle joint sense
Dorsal spinocerebellar
Proprioception
Ventral spinocerebellar
Provide input to the
cerebellum
Lateral corticospinal
Voluntary skilled
movement of trunk and hind limbs
Ventral corticospinal
Voluntary skilled
movement of forelimb
Tectospinal
Reflex postural movement
in response to visual stimuli
Rubrospinal
Facilitate activity of flexor muscles and inhibits extensors
Vestibulospinal tract
Facilitates activity of extensor muscles and inhibition
of flexor muscles under the influence of the ear and
cerebellum in maintenance of balance
Click the play button
to view a movie on Lumbar Laminectomy.
The 31 pairs of
human spinal nerves arise from the fusions of the
ventral and dorsal roots of the spinal cord. The nerves
are named according to their point of emergence. All
spinal nerves are mixed nerves because the ventral roots
contain myelinated axons of motor neurons located in the
cord and the dorsal roots carry sensory fibers entering
the cord.
After emerging,
each nerve divides into dorsal and ventral rami. The
rami contain both motor and sensory fibers. The dorsal
rami serve the skin and musculature of the posterior
body trunk close to their level of emergence. The
ventral rami of spinal nerves T2
- T12
pass anteriorly as the intercostal nerves to supply the
muscles of intercostal spaces and the skin and muscles
of the anterior and lateral trunk. The ventral rami of
all other spinal nerves form nerve networks called
plexuses. These plexuses serve the motor and sensory
functions of the muscles and the skin of the limbs. The
fibers of the ventral rami combine in the plexuses. The
plexuses fibers diverge to form peripheral nerves, each
of which contains fibers from more than one spinal
nerve. The major plexus we will study are the:
Cervical Plexus and the
Neck
Brachial Plexus and Upper Limb
Lumbar Plexus and Lower Limb
Sacral Plexus and Lower Limb
The cervlcal plexus arises from the ventral rami of C1
through C5 to supply muscles of the shoulder
and neck.
The major motor branch of this plexus
is the phrenic nerve, which arises from C3-C4
(and some fibers from C5)
and passes into the thoracic cavity in front of the
first rib to innervate the diaphragm. The danger of a
broken neck is that the phrenic nerve may be severed,
leading to paralysis of the diaphragm and cessation of
breathing.
SKETCH
5
**Using
images in this lab and your textbook, sketch the
cevical plexus and label the following:
C1-C6, Phrenic nerve
The brachial plexus emerges from the
ventral rami of C5
thorough C8
and T1.
The plexus is subdivided into four major peripheral
nerves: the axillary nerve, radial nerve, median nerve
and the ulnar nerve. Trauma to the ulnar nerve produces
a smarting sensation commonly referred to as “hitting
the funny bone.” Repeated use and or trauma to the
median nerve in the area of the wrist can result in
Carpal Tunnel Syndrome.
SKETCH
6 **Using
images in this lab and your textbook, sketch the
brachial plexus and label the following:
C5-C8, T1, Axillary nerve, Radial
nerve,
Median nerve, Ulnar nerve
FIGURE 2.13 Brachial Plexus
Click the play button to
view the movie to the right describing the types of
surgery performed to alleviate the pain
associated with Carpal Tunnel Syndrome which
involves the median nerve.
An alternative view
for this animation is given below:
The lumbar plexus arises from ventral
rami of L1
through L4.
The largest nerve of this plexus is the
femoral nerve,
which passes beneath the inguinal ligament to innervate
the anterior thigh muscles.
SKETCH
7
**Using
images in this lab and your textbook as well as the
models in class, sketch the lumbar plexus and label
the following:
L1-L4, Femoral nerve, Saphenous nerve
Arising from L4
through S4,
the nerves of the sacral plexus supply the buttock, the
posterior surface of the thigh, and virtually all
sensory and motor fibers of the leg and foot. The major
peripheral nerve of this plexus is the sciatic nerve,
the largest nerve in the body.
SKETCH
8
**Using
images in this lab and your textbook, sketch the
sacral plexus and label the following:
L4-L5, S1-S4, Sciatic nerve, Sural
nerve, Tibial nerve
FIGURE 2.15 Sacral Plexus
Click the play button to
view the movie to the right discussing a therapy which works to alleviate the
symptoms of Sciatica which is an inflammation of the
Sciatic Nerve.
An alternative view
for this animation is given below:
The autonomic nervous
system is the subdivision of
the peripheral nervous system that regulates body
activities that are for the most part not under
conscious control. It is composed of motor neurons
serving cardiac muscle, smooth muscle and internal
glands. This system is often referred to as the involuntary nervous
system, because these
structures typically function without conscious control.
There is a basic anatomical
difference between the motor pathways of the somatic
(voluntary) nervous system and those of the autonomic
nervous system. In the somatic division, the cell bodies
of the motor neurons reside in the spinal cord or brain,
and their axons sheathed in spinal nerves extend all the
way to the skeletal muscles they serve. The autonomic
nervous system consists of sequences of two motor
neurons. The first motor neuron of each pair
(pre-ganglionic neuron) resides in the brain or spinal
cord. Its axon leaves the central nervous system to
synapse with the second motor neuron (postganglionic
neuron), whose cell body is located in a ganglion
outside the central nervous system. The axon of the
postganglionic neuron then extends to the organ it
serves.
The autonomic nervous system has two
subdivisions. The sympathetic and parasympathetic
divisions serve most of the same organs, but generally
cause opposing effects.
FIGURE 2.16 Three Dimensional Spinal Cord Nerve
Most body organs served by the autonomic nervous system
receive fibers from both the sympathetic and
parasympathetic divisions. The only exceptions are the
organs of the skin (sweat glands and arrector pili
muscles attached to the hair follicles), the pancreas
and liver, the adrenal medulla, and essentially all
blood vessels. When both divisions serve an organ, they
have opposing effects. This is because their
postganglionic axons release different
neurotransmitters. The parasympathetic fibers (cholinergic
fibers) release acetylcholine. The sympathetic
postganglionic fibers (adrenergic fibers) release
norepinephrine.
The parasympathetic
division is often called the “resting and digesting”
system because it maintains the visceral organs in a
normal function state. The sympathetic division is
sometimes referred to as the
“fight or flight” system because it prepares the body to
cope with events that threaten homeostasis. Under
emergency conditions, the sympathetic nervous system
provides for an increase in heart rate and blood
pressure, dilates the bronchioles of the lungs,
increases blood sugar levels, and promotes other effects
that help the individual cope with a stressor.
TABLE
2 **Using
your textbook and other resources, list the effect of
the parasympathetic and sympathetic nervous system
(i.e., Inhibit (slow
down) or stimulate (speed
up)) on each
of the organs listed on the Autonomic Nervous System
Chart. You can use
the chart provided by using the link given below.
The Autonomic Nervous System Chart is available
by printing out the Sketches Tables Charts Form
Read the
following articles and view the provided videos given in
the links below. The articles and videos will assist you
in answering the questions on Spinal Cord Regeneration.
Click the play button to
view the movie to the right on the future of spinal cord
regeneration from Stephen Davies of the University of
Colorado Denver School of Medicine.
An alternative view
for this animation is given below:
Click the play button to
view the movie to the right on the future of spinal cord
regeneration from
Dr. Hans Kierstead professor of anatomy and neurobiology
at the University of California, Irvine.
.
An alternative view
for this animation is given below:
QUESTIONS
**Spinal
Cord Regeneration Questions 1)
Describe in your own words the process used in the
successful treatment of spinal cord regeneration in
rats. 2) How is the process in cat spinal cord rehabilitation
using embryonic tissue different than the treatments
used in rats? 3) Describe how the use of
microcomputers and computer technology is used in spinal
cord rehabilitation? 4) Describe why nerve tracts in the arm or hand if
severed or damaged are able to repair themselves while
those in the brain or spinal cord cannot regenerate.
The Spinal Cord Regeneration is
available by printing out the Questions Form
8)
Spinal Cord Disorders View the following
three tutorials of Diseases
and Conditions of
the Spinal Cord and produce a chart for each which
summarizes the main points for tutorial. You need to use
the Charts that are supplied in the links below.
