Anatomy and physiology labs

EXPERIMENT 8: FETAL PIG DISSECTION - MUSCULAR SYSTEM In this experiment, you will become familiar with the muscular system of the fetal pig. This muscular system closely resembles that of the human body and thus will allow for a hands-on examination of key muscles.

PROCEDURE 1. To begin, lay down your underpad and place your dissecting tray on top of it. Be sure you have all of your safety equipment

on before beginning.

2. Once prepared, gently open the bag your pig is in.

Note: DO NOT destroy this bag or empty out the preserving solution within the bag. You will need it for the whole semester.

3. Lay your pig onto the dissecting tray, ventral side facing up. Slide the strings over the dissection tray to hold the pig in place.

4. To view the muscular system, you must cut away the pig’s skin.

5. Using a scalpel, make a skin-deep incision running from the umbilical cord to the neck of the pig. DO NOT cut through the muscular tissue below the skin. Some areas may require more time, but be patient to ensure the best cuts are made. If you accidentally cut too deeply move on – it will be okay!

6. Use Figure 9 as a guide for the incisions required to remove the skin from the pig.

7. Begin by pulling slightly upward on the umbilical cord. Starting just below the about 1 cm superior to the umbilical cord, cut away from your body along the mid-ventral line toward the neck (Figure 9; insertion 1). Trace a circle 1 cm around the umbilical cord.

Note: Use caution when cutting around the neck region.

8. The second cut will vary based on the sex of your pig. Follow the lines shown in Figure 9. For males, use 2M and for females, use 2F.

9. Cut along the jawline (Figure 9, insertion 3). When you turn the pig over, you will complete this incision around the dorsal side of the fetal pig.

10. Make a lateral cut at the level of the hindlimbs (Figure 9, insertion 4), then another just below the ribcage (Figure 9, insertion 5).

11. Make an incision up each limb (Figure 9, insertions 6 and 7). Cut completely around each limb at the distal ends.

Experiment 8Fetal Pig Dissection - Muscular System Materials Fetal Pig

Dissection Tray

Dissection Tool Kit

String (attached to pig’s hooves)

Experiment Inventory

12. Carefully peel away the skin from the underlying muscle. Use the scalpel and blunt probe to break the connective tissue holding the skin to the fascia. Use scissors to remove any skin flaps.

13. Remove the strings from the dissection tray, and turn the pig over so its dorsal side is facing up.

14. Re-secure the strings underneath the dissection tray.

15. Make a shallow cut along the mid-dorsal line along the backbone.

16. Again, carefully peel away the skin from the underlying muscle using the scalpel and blunt probe to break the connective tissue holding the skin to the fascia.

17. If a whitish layer of adipose tissue is preventing your view of the muscle, using a teasing needle to gently remove the tissue and reveal the underlying muscle. You may need to wipe the whitish adipose from the muscle with a paper towel.

18. Pat the muscles dry with a paper towel, and examine the muscles of the shoulder, hind leg, chest, back, and abdomen. You should be able to see the fibrous structure of the muscle tissue. Pay special attention to the points of origin and insertion, as well as how they act. Remember the following terms:

Adductors – Pull a body part toward the midline of the body. Abductors – Pull a body part away from the midline of the body. Flexors – Bend a body part against another body part to reduce the angle between them. Extensors – Straighten a body part to increase the angle between two body parts. Constrictors – Contract a body part to shorten it.

19. Complete Table 4 at the end of the experiment.

Figure 9: Cut lines for skinning the fetal pig.

20. Take a picture of your pig in the dissection tray for the upload document. Make sure that your name and access code are handwritten on a piece of paper that is clearly visible in the background of the photograph.

21. To finish, locate the bag the pig came in. Gently place the pig back into the bag, and tightly secure the bag with a rubber band, or place the pig in the zip-seal bag provided in the dissection box.

22. Place the pig back into the cool environment you had previously stored it in. Remember, the best place to keep the pig is in a cool, dark place.

23. After your pig has been put away, clean off your dissecting tray and dissecting tools with soap and water. Biological scraps should not be thrown into the garbage. Securely store the biological scraps until the end of the term so that they can be properly disposed of at one time.

24. Clean the area in which you worked with soap and water. As long as the underpad has not been damaged, keep it for future experiments.

Muscle Origin Insertion Movement

Pectoralis major

Latissimus dorsi

Deltoids

Rectus abdominis Transverse ab-

dominis Gluteus medius

Data SheetExperiment 8 Data Sheet Table 4: Experimental Data