Mammalian Dissection: Fetal Pig
Integrated Science 4
1/09
Name ____________________________ Per. _______
Introduction
Organisms are classified based on similarities and differences to: 1) make sense of the millions of organisms on
record, and 2) predict the evolutionary relationships among them. In this laboratory, you will gather evidence
on a mammal’s (fetal pig’s) anatomy and physiology as a basis for comparison with other vertebrates.
Pre-Laboratory
Part A. External Anatomy
Use your Biology book p. 559-560 and http://www.whitman.edu/biology/vpd/main.html or other available
resources to label the following items on the diagram below.
1. Label the following regions: dorsal, ventral, anterior, posterior, cranial region, pectoral region, pelvic region,
and caudal region. In addition, note the areas where the thoracic cavity and abdominal cavity are found.
2. Label these external structures: umbilical cord, snout (nares), eye, ear (pinna), mouth, leg, hoof, anus.
Part B. Tools
Read and highlight the Laboratory Procedures, Part A, B, C and D below. Then, describe the appropriate use
of each of the tools listed below being used during the dissection. Additional information can be found online.
Dissection Scissors
Dissecting Probes
Scalpel/Blade
Dissecting Pins
Dissecting Tray
Part C. Respect Pledge
I hereby pledge to treat the specimen with utmost respect and use all dissection tools for their appropriate
function. If I do not uphold this pledge, I understand I will receive a zero for the assignment and an office
referral. I may elect to do an alternate assignment.
Signed:
Laboratory
Part A. Procedures
Beginning of each dissection day:
1. Obtain specimen, gloves, pins (about 8), and dissection kit (with scissors,
probe(s), scalpel/blade).
Dissection:
2. Place the specimen on its dorsal side on a dissecting tray. One or two group
members should hold apart the specimen’s legs while another group member
makes incisions through the body wall in the order shown in the figure to the
right (numbers 1-4). Make initial incisions with scalpel/blade and longer cuts
with scissors. Be careful to cut around the umbilical cord and make your cuts
deep enough (use scissors) to cut just through the muscles. Pin the flaps of
muscles away to expose the abdominal cavity and other internal cavities.
3. To expose the thoracic cavity make a horseshoe cut out of the ribs with the
blunt-tipped dissecting scissors as shown on the figure with the dotted line. To
identify gender, look for the urogenital papilla on the posterior end ventral to the
anus and tail. If it is there, your pig is female. If not, it is male. Follow
additional instructions for dissection in handouts or from your teacher. You
can also go online to the website above (see Pre-Laboratory, Part A).
5
umbilical cord
anus
urogenital papilla
Part B. Observations/Data
1. Observe your dissected mammal specimen (fetal pig). On the attached Specimen Drawing templates, color
and label structures from each of the major organ systems as indicated. Drawings must have a title and a
scale. Dissection manuals will be available to help you.
Part C. Structure and Function
1. Describe the function and location of the organs listed below that you identified during your dissection of
the fetal pig. Use the Dissection Guide provided for you and your biology book for information.
 Cardiovascular System
1. Structure: Heart
Function:
Location in Fetal Pig:
2. Structure: Arteries
Function:
Location in Fetal Pig:
3. Structure: Veins
Function:
Location in Fetal Pig:
 Respiratory System
4. Structure: Trachea
Function:
Location in Fetal Pig:
5. Structure: Lungs
Function:
Location in Fetal Pig:
6. Structure: *Diaphragm
Function:
Location in Fetal Pig:
 Digestive System
7. Structure: Stomach
Function:
Location in Fetal Pig:
8. Structure: Liver
Function:
Location in Fetal Pig:
9. Structure: Pancreas
Function:
Location in Fetal Pig:
10. Structure: Small Intestine
Function:
Location in Fetal Pig:
11. Structure: Large Intestine
Function:
Location in Fetal Pig:
12. Structure: Cecum
Function:
Location in Fetal Pig:
13. Structure: Rectum
Function:
Location in Fetal Pig:
 Lymphatic System
14. Structure: Spleen
Function:
Location in Fetal Pig:
 Urinary System
15. Structure: Kidney
Function:
Location in Fetal Pig:
16. Structure: Ureter
Function:
Location in Fetal Pig:
17. Structure: Urinary Bladder
Function:
Location in Fetal Pig:
 Reproductive System
18. Structure: Testes
Function:
Location in Male Fetal Pig:
19. Structure: Penis
Function:
Location in Male Fetal Pig:
20. Structure: Urethra
Function:
Location in Male Fetal Pig:
21. Structure: Ovary
Function:
Location in Female Fetal Pig:
22. Structure: Uterus
Function:
Location in Female Fetal Pig:
Part D. Clean up
At the end of each dissecting day, return you specimen to a plastic bag, saving all of the dissecting fluid. Clean
and dry lab tray, tools, and work area. This will be checked by your teacher. Clean out the sink at your lab
station. Wash hands!
Discussion
1. Complete the table below, considering adaptations observed during the laboratory activity.
Adaptation
Example:
Fat and Fur
Function
Body Insulation
Evolutionary Importance and/or Evidence of Specimen’s Metabolic
Rate.
Thick layers of fat and hair help retain body heat. This is an important adaptation for
endothermic organisms because it helps to prevent heat loss.
1.
2.
3.
4.
5.
2. Consider your responses above. How are the structures you identified different from structures in
organisms that use a different metabolic system?
Specimen Drawings
Organ System
Color
Cavity
(where primarily found)
Organs
(draw and label, identify on specimen,
know function)
Cardiovascular/ Circulatory
Respiratory
Thoracic
Heart, Blood Vessel (artery or vein)
Thoracic
Digestive
Abdominal (ventral)
Urinary/ Excretory
Abdominal (dorsal)
Reproductive
Abdominal (dorsal)
Trachea , Lungs
Stomach, Liver, Pancreas, Small Intestines, Large
Intestines, Rectum, Cecum
Kidney, Ureter, Urinary Bladder
Male: Testes, Urethra
Female: Ovary , Oviduct, Uterus
Ventral View
Location: Thoracic and
Abdominal Cavities
Scale:
Sex: Female
Ventral View of Dorsal Organs
Location: Abdominal Cavity
Scale:
Sex: Male
Ventral View of Dorsal Organs
Location: Abdominal Cavity
Scale: