Download PigDissectionLab 5Brain

FETAL PIG DISSECTION - LAB # 5
BRAIN AND SPINAL CORD
PSSA Standards for Reading, Writing, Speaking, Listening, Science and Technology
ASRWSL 1.1F = Understand the meaning of and apply key vocabulary across the various subject areas.
ASRWSL 1.2A = Read and understand essential content of informational texts and documents in all
academic areas.
ASRWSL 1.6A = Listen to others.
ASRWSL 1.6D = Contribute to discussions.
ASRWSL 1.6E = Participate in small and large group discussions and presentations.
ASST 3.2 C = Apply the elements of scientific inquiry to solve problems.
ASST 3.3 A = Explain the structural and functional similarities and differences found among living things.
ASST 3.7 A = Identify and safely use a variety of tools, basic machines, materials and techniques to solve
problems and answer questions.
MATERIALS: scalpel
safety goggles / glasses
forceps (tweezers)
Fetal Pig Reference Diagram Booklet
scissors
lead & colored pencils
probe
bone cutters (needed to remove skull)
pig
dissection pan lined with paper toweling
1 rough draft diagram entitled:
BRAIN AND SPINAL CORD – DORSAL / VENTRAL / LATERAL VIEWS
GENERAL INFORMATION:
This lab is divided into two parts:
PART I = You are going to remove the skull and extract the brain and spinal cord
PART II = you are going to locate, draw, dissect and label parts of the brain.
The labeled, colored diagrams completed in PART II make up the lab report for this portion of the
fetal pig dissection.
PART I
Removing the Brain and Spinal Cord from the Skull and Vertebral Column
You should have already removed the skin and muscle from the head of your pig. If you did not,
please do so at this time.
1. Hold the pig’s head so that the snout faces the front of the room. Locate the vertebral column
and look into the severed end. You should be able to see the spinal cord surrounded by the
vertebral column. The cord is a light colored tube of nerve tissue. Open the scissors and carefully
insert one blade point inside the vertebral column so that it is between the spinal cord and the
bone on the right side. Cut through this side of the vertebral column. Do not cut or damage the
spinal cord!! Repeat the procedure on the left side.
2. The next step is to peel off the dorsal side (top) of the vertebral column. However, the spinal
cord is surrounded by a thick, opaque membrane. This membrane also covers the brain. It forms
a protective layer called the meninges that is usually stuck to the underside of the vertebrae and
skull. There are also nerves that extend through the vertebrae. Carefully loosen the membrane
and nerves with the scalpel first and then remove the top of the vertebral column. This should
expose the spinal cord and any nerves that branch off it. Try not to remove the meninges as you
proceed because it helps hold the brain and spinal cord together. You will have to remove it after
the brain is extracted in order to identify the parts.
3. You are now going to cut a "lid" out of the pig’s skull (like cutting a lid out of a Halloween
pumpkin). Hold the pig’s head so that you are looking at the snout and eyes. Using the bone
cutters, start at the inner corner of one eye socket and work toward the inner corner of the
opposite eye socket. Carefully scrape and snip the bone so that it is cut part of the way through.
Be careful not to cut too deep because it is very easy to damage the brain which is like pudding in
consistency. After you have reached the inner edge of the opposite eye socket, continue scraping
and snipping the top of the eye socket, all the way around the back of the head, and over the top
edge of the opposite eye socket. When you are done you should have “carved” a lid on the top of
the skull, but not snipped deep enough to damage the brain. Once you have made this initial
carving, use the scissors to carefully finish cutting through the bone. Try not to cut through the
meninges that covers the brain.
4. Use scissors to cut the suture lines in the top of the skull. This will divide it into four quarters.
Starting in the center of the top of the skull, peel the quarters of skull off the top of the head (like
peeling the skin off an orange). The meninges will stick to the underside of the skull. You may
have to use a scalpel to separate it from the inside of the skull. From this point on, you have to cut
and peel off portions of the skull until the brain and spinal cord are exposed. There is no set way to
complete this task. You may find it easier to hold the pig’s head in the palm of your hand, or to
hold the snout as if it is a handle. Do not remove the eyes at this time. You have successfully
completed this step when only the bottom third of the skull remains.
5. If the pig’s head is small, continue to use the snout as a handle. If the pig’s head is larger, cut
off the snout in the following way. Use the bone cutters to break the bone, and then use the
scissors to complete the job. Carefully cut away any remaining muscle, bone and cartilage from
the front of the skull.
6. Turn the brain upside-down. Gravity should help pull the brain away from the remaining skull.
Loosen the brain from the bottom of the skull by severing the large nerves that anchor it to the
skull. This includes the optic nerves that extend from each eye into the brain. Remove the brain /
spinal cord from what remains of your pigs head. You can also remove any meninges that are still
present. Refer to diagram # 21 in the Reference Diagram Booklet.
PART II
Brain and Spinal Cord
REFER TO DIAGRAM # 20 and # 21 in the Reference Diagram Booklet.
Use the rough draft diagram entitled: BRAIN AND SPINAL CORD - DORSAL / VENTRAL /
LONGITUDINAL VIEWS to complete the next section.
1. Place the brain in the pan so that you are looking at the top of the head (dorsal side). The
surface of the brain is convoluted. It has many ridges called gyri (singular = gyrus) and many
grooves (indentations) called sulci (singular = sulcus). The largest portion of the brain is the
cerebrum. It is divided into two halves called cerebral hemispheres. It is divided by a deep
indentation called the longitudinal fissure which runs down the center of the cerebrum from
anterior to posterior. The cerebral hemispheres are held together by a bridge of connective tissue
called the corpus callosum. You will be cutting the corpus callosum later in the dissection. The
gyri and sulci are part of the cerebrum. The surface of the brain is called the cerebral cortex.
2. Posterior to the cerebrum is the cerebellum. It is much smaller than the cerebrum. It is
separated from the cerebrum by a deep indentation called the transverse fissure that runs from
the left side to the right side. The first part of the spinal cord is slightly wider than the rest of the
cord. This wide area is the medulla oblongata. A lot more of the medulla oblongata will be seen
when you turn the brain over to do the ventral view diagram.
3. Draw a dorsal view of the brain and spinal cord in the designated area.
Label the following:
cerebrum
gyrus
longitudinal fissure
sulcus
transverse fissure
medulla oblongata
cerebellum
spinal cord
4. Turn the brain over so that you are looking at the ventral side. Most of what you see is
cerebrum. Use the ventral view picture on diagram page # 21 to help you locate the optic tract and
medulla oblongata. The medulla oblongata extends from the spinal cord and covers the middle of
the cerebellum on this side of the brain. Only a small portion of the cerebellum on the left and
right side of the medulla oblongata is visible from this view. Between the medulla oblongata and
the optic tract there are two different areas of tissue. The pons is a small region of tissue that
connects to the medulla oblongata. Between the pons and the optic tract is an area of brain tissue
that is considered part of the cerebrum for this dissection.
Draw a ventral view of the brain and spinal cord in the designated area.
Label the following:
cerebrum
pons
cerebellum
medulla oblongata
optic tract
spinal cord
5. You are now going to cut the brain in half longitudinally. Turn the brain so that the dorsal side
faces the ceiling. Cut down through the longitudinal fissure (front to back). You will sever the
corpus callosum that holds the cerebral hemispheres together. The remains of this structure are
visible on the inside of the brain. Continue to cut through the cerebellum and spinal cord. Use
diagram # 22 in the Reference Diagram Booklet to help you draw and label the inside of one half
of the brain and spinal cord.
Label the following:
cerebrum
gyrus
spinal cord
cerebellum
corpus callosum
sulcus
transverse fissure
6. Remove an eyeball and pop out the lens. It looks like a cherry pit. You can now get rid of
anything that remains of your pig.
NOW YOU ARE DONE……………AMEN !!!
OVER 
FETAL PIG DISSECTION LAB REPORT # 5 (40 points):
 THIS IS NOT A GROUP LAB REPORT. 
 EACH PERSON IN THE CLASS MUST TURN IN A LAB REPORT . 
This lab report consists of one final draft diagram page. Each person in the group must have one
diagram page to turn in. Photocopies receive zero credit. The diagrams are graded according to
the following criteria:
accuracy of the drawings
neatness and correct spelling of labels
accuracy and legibility of labels
following the directions
1). Once you complete the rough draft page, get a clean copy to make your final draft.
Directions for the diagram page follows. Remember that the gyrus and sulcus are parts of the
cerebrum. The fissures are indentations (spaces) between structures and should not be colored.
PAGE 1 – BRAIN AND SPINAL CORD – DORSAL / VENTRAL / LATERAL VIEWS
DORSAL VIEW= Use either a black colored pencil or black pen to outline and label
the structures. Use either a black colored pencil or black pen and a ruler to draw lines
from the labels to the structures. The lines should not cross over each other. Color the
cerebrum red, cerebellum blue, medulla oblongata orange and spinal cord green.
VENTRAL VIEW= Use either a black colored pencil or black pen to outline and label
the structures. Use either a black colored pencil or black pen and a ruler to draw lines
from the labels to the structures. The lines should not cross over each other.
Use the same colors that you used for the dorsal view but color the optic tract
yellow and the pons purple. Remember that the area between the optic tact and
pons is considered part of the cerebrum.
LATERAL VIEW = Use either a black colored pencil or black pen to outline and label
the structures. Use either a black colored pencil or black pen and a ruler to draw lines
from the labels to the structures. The lines should not cross over each other.
Color the cerebellum blue. Color the spinal cord plus the areas labeled medulla
oblongata and pons on diagram #22 in the Reference Diagram Booklet green.
Color the rest of the diagram red.
BRAIN AND SPINAL CORD - DORSAL / VENTRAL / LATERAL VIEWS
BRAIN / SPINAL CORD - DORSAL VIEW
BRAIN / SPINAL CORD - VENTRAL VIEW
BRAIN / SPINAL CORD - LONGITUDINAL SECTION