Surgery Final Day – Nervous System
Brain Surgery– Extra Credit
This section is to be completed only if your group finishes the previous sections with class time to spare.
Did she say BRAIN Surgery?
. The brain of the fetal pig is difficult to examine, because it is not fully developed. It is possible, however, to
cut the dorsal surface of the cranium to reveal the cerebrum, cerebellum, and medulla. If your instructor
approves this dissection, use the figure to identify the parts of the brain.
Procedure: To view the anatomy of the brain it is necessary to remove the skin and top of the skull from the pig
with your scalpel and scissors.
1.
Place your patient with its dorsal side up or on its stomach.
2. Begin your dissection by using your scalpel to lightly trace the cutline shown on Figure 3. The cutline should
extend around the top of the head from the top of the pig’s nose to the base of the ears. Make sure your cut
extends below the eyes (see Photo 4). You will use this line as a guide to make your incision.
3. For the incision, lift the skin to be cut with your forceps and make a slit with your scalpel. Insert your scissors
into this slit and cut along the cutline you previously traced.
4. Expose the entire cranium
5. Using all of your skill as surgeons, carefully expose the brain. The brain will require slow and meticulous removal
of the skull piece by piece.
6. At the top of the cranium use the scalpel to cut the skin and fibrous covering along the mid dorsal line
7. Cut around the top of the skull (above the eyes) as shown on Photo 4 and remove the top of the skull. . DO
NOT PENETRATE TOO DEEPLY. The skull is thin at top and gets thicker as you work downward use a pair of
scissors to make the first nicks in the skull.
8. . Continue to break and remove fragments with your forceps until the brain is exposed
9. Remove the tissues covering the brain carefully to avoid damaging the brain
10. Continue to dissect the cranium and remove the entire brain. If successful then divide it into two halves
11. Study the brain or diagrams and identify the cerebrum, cerebellum, medulla, and corpus
the diagram.
12. make an incision through the pupil until the scalpel touches the hard lens.
13. Using tweezers and your scalpel, tease the lens out of the eye.
callosum. Label on
Name_____________________________Date_____________Per.______
EXTRA CREDIT: Nervous System
Why is the skull so hard?_________________________________________________________
Once you have exposed the brain ,Draw a picture of the brain in this space.
Fetal Pig Brain
Practice identifying these structures using Photo 4. When each member of your group is able to identify all of
these structures, ask your instructor to quiz your group so that you can receive a stamp for this
When all of your group is ready, call your teacher over to be checked off.
Organ
longitudinal fissure
right cerebral hemisphere
left cerebral hemisphere
cerebellum
Medulla –oblongata
pupil
lens
Iris
eye
–
Extra Credit. Review Questions
Answer the following questions based
necessary)
1.
Check off
a dividing line along the top of the brain which divides the
brain into right and left hemispheres (sides
the right half of the cerebrum
– the left half of the cerebrum
the portion of the brain located behind the cerebrum
located at the center of the eye
a hard structure located within the eye
Generally the colored part of the eye
– located on either side of the head
upon your prior knowledge of anatomy (you may use your book if
What does the word hemisphere mean?
2. What does the longitudinal fissure divide?
3. What is the primary function of the skull?
4. What are three things the cerebrum does?
5. List two functions of the cerebellum.
6. Why is the brain completely encased in bone
7.
Why does the pupil change size?
8.
Where does the lens focus light?
NERVOUS SYSTEM
Locate and identify:
Brain
Spinal Cord
1. Place the fetal pig on the dissection tray with the dorsal surface upward. It is necessary to exercise
extreme caution in doing this dissection. It is very easy to injure the delicate brain tissue. If time permits
for extra credit you may remove the entire brain and in one piece.
3. Are there any blood vessels on the surface of the brain? _________________________
4. The brain is divided into two halves by the longitudinal fissure. What are the 2 parts? _________________
5. The outer surface of the brain has many folds. What is the technical name for these folds?
____________ Did the frog have them? _________________
Explain.___________________________________________________________________________
Fetal Pig Brain
7. How many spinal nerves are in the fetal pig?
8. What covers the spinal cord? ___________________
____________________
9. What nerves are responsible for the fight-or-flight response? __________________________