Surgery Day 3 – Brain and Spinal Cord by linzhengnd


									                                     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       callosum. Label on
    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.

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                                                                                                 Check off
longitudinal fissure                   a dividing line along the top of the brain which divides the
                                       brain into right and left hemispheres (sides
right cerebral hemisphere              the right half of the cerebrum
left cerebral hemisphere               – the left half of the cerebrum

cerebellum                             the portion of the brain located behind the cerebrum
Medulla –oblongata
pupil                                  located at the center of the eye
lens                                   a hard structure located within the eye
Iris                                   Generally the colored part of the eye
eye                                    – located on either side of the head
Extra Credit. Review Questions
Answer the following questions based   upon your prior knowledge of anatomy (you may use your book if

   1.   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?

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? _________________

                          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? __________________________

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