HOM Lesson 6-Unit3
Living Environment Fetal Pig Lab
Before beginning a dissection, it is important to have an understanding of some of the basic directional
terminology associated with the dissection of specimens.
Key Anatomical Directions
TASK: List three safety precautions needed when doing the fetal pig dissection and state using a
complete sentence the specific purpose of each precaution.
TASK: List the purpose of this lab.
Procedure:
1. Place specimen in a dissection tray. Tie a piece of twine to a front and back leg. Pass the twine
underneath the dissection pan to the other side and tie it to the leg on the opposite side to hold the legs
apart.
2. Use a metric ruler to measure the length of your fetal pig. Use the information below to determine
the approximate time from conception of your pig.
The period of pregnancy or gestation for pigs is 112-115 days
(3 months, 3 weeks, 3 days) and each female may produce a litter of 7-12. As the period of
development proceeds, the pig embryos get longer, so an approximate age may be calculated from the
length. (from Odlaug: Laboratory Anatomy of the Fetal Pig, William C. Brown, 1955.)
1
HOM Lesson 6-Unit3
Average Development Rate of the Fetal Pig
Time from Conception
21 days
35 days
49 days
56 days
100 days
114 days (birth)
Pig Length in mm
11 mm
17 mm
28 mm
40 mm
220 mm
300 mm
4. Make incisions to open the thoracic and abdominal cavities. This should be done with scissors. Use
the diagram of the ventral cuts of a fetal pig dissection to assist this.
Do not use razor blades or a scalpel!. Keep the
scissors parallel to the skin surface to prevent
damage to the internal organs. Remove the flaps of skin to the internal organs.
Identify any 10 of the following internal organs in your fetal pig for your teacher. (thymus gland, heart,
lungs, diaphragm, stomach, small intestine, large intestine, spleen, gall bladder, umbilical cord, ureter,
and pancreas)
2
HOM Lesson 6-Unit3
Post Lab:
1.)
Identify the structures on the diagram of some selected organs in the fetal pig.
2.) Complete the table which follows.
Organ
Function
Body System
brain
Heart
Lungs
stomach
Liver
gall bladder
3
HOM Lesson 6-Unit3
Small intestine
esophagus
large intestine
kidneys
pancreas
Testes/ovaries
3.) Define the terms dorsal, ventral, anterior, and posterior.
4.) Graph the developmental rates of both the fetal pig and the human embryo/fetus
on the graph provided. Remember to use a proper scale, title your graph, label
your axes, and key your graph.
Average Development Rate of the Fetal Pig
Time from Conception
21 days
35 days
49 days
56 days
100 days
114 days (birth)
Pig Length in mm
11 mm
17 mm
28 mm
40 mm
220 mm
300 mm
The data below provides a comparison of the average development rate of a human fetus.
Average Development Rate of a Human Embryo/Fetus
Time from Conception
70 days
98 days
124 days
168 days
210 days
252 days
Fetal Length in mm (avg length)
61 mm.
120 mm
160 mm.
230 mm
280 mm
340 mm
4
HOM Lesson 6-Unit3
5.) How does the growth rate of the last HALF of a fetal pig's development compare with that of a
human embryo in the HALF of a pregnancy?
5