SBI3U/C – Animals: Structure and Function Unit
Dissection Date: _____________________
Dissection and Anatomy of a Vertebrate Mammal: The Fetal Pig
EXPECTATIONS
Safety
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Please DO NOT wear contact lenses during the dissection – formalin gas gets behind the lens and may
potentially cause eye damage.
Safety goggles and gloves must be worn at all times. No direct skin contact.
Pigs and/or their dissected body parts are NOT to be removed from the classroom at anytime
No horseplay or fooling around of any kind will be tolerated. Follow instructions as written.
Immediately report any injuries, no matter how minor to the teacher
Absolutely no food, water or gum is permitted.
Avoid wearing baggy clothes. Tie back long hair.
Clean-Up
 You will be assigned a Dissection Kit with a specific number. It is your responsibility to keep this kit
clean and dried. This also applies to your workspace – Both the kit and the lab bench must be cleaned
with soap and dried, and verified by your teacher. Failure to do so will result in one lost mark per time
for each group member.
 Lab benches will be assigned a sink – It is the responsibility of ALL groups to make sure that the sink is
clear of any t-pins, body parts or other debris BEFORE you leave. One mark will be deducted for each
group member – Work together to keep your areas clean.
 In case you are not finish with the dissection:
o Wrap the pig in moistened paper towels and place into a zip-log bag.
o Wash and dry your gloves with your gloves on. Write your name on a paper towel and wrap
your gloves in it. Place zip-loc bag (with pig) and gloves into a labeled plastic bag.
 DO NOT THROW AWAY DISSECTED PARTS – they are a biohazard and must be properly disposed of.
Place all dissected parts back into the pig. The teacher may ask to view them during the dissection
 Wash your hands before leaving the lab.
Missed Lab Sessions
 Each one of you is required to do the dissection (or alternate assignment). You will not be given marks
for an experiment you have not been present for; therefore, if you miss a dissection class, you must
make it up! Failure to do so will result in a mark of zero for the lab portion of this activity.
 Make-up dates will be at lunch on: _______________________________________________________
Tentative Distribution of Marks
Criteria
Marks Allotted
Pre-Lab Quiz
7
Journal Log
5
Performing, clean-up, etc. the dissection
3
Quality of the dissection (clean cuts, using correct tools,
tissues not destroyed, etc)
10
PowerPoint Dissection Quiz
Total
15
40 Inquiry
= 5% final mark
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Dissection Pre-Lab Questions
1. What is the purpose of this dissection?
2. What 2 pieces of safety equipment must you wear at all times during the dissections?
3, If the preservatives touches your skin, what should you do immediately?
4. Why should you wash your hands, wipe down the lab bench and make sure all tools are scrupulously clean
and dry after dissection?
5. Before you attach the pig to the tray what are you supposed to do according to the instructions? (be
specific)
6. How are you to attach the pig to the dissection tray?
7. What instrument must you use for your first cut? Why?
8. Which portion of the body will you be working on first?
9. What must you do, if you are injured during this lab (even if you have a paper cut)?
10. What should you do if you finish early?
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SBI3U/C – Animals: Structure and Function
Date: _____________________________
Fetal Pig Dissection
Adapted from Biology 11, R. Bowers et al, Addison-Wesley, 2002
Animals used for scientific research and dissection help us to understand our own bodies and how they function in
health and disease. The fetal pig will be used as a representative mammal. As a fetus, the pig receives nutrients and
oxygen from its mother through the umbilical cord. Read the safety and dissection directions carefully.
Purpose:
To study the external and internal anatomy of the fetal pig to gain perspectives on the following:
 relative positions and sizes of organs
 interrelations between organs and organ systems
 scientific process of dissection and its applications for anatomy and physiology.
IMPORTANT:
 Please read through the expectations and safety guidelines located AT THE FRONT OF THIS PACKAGE before
conducting the dissection
Materials:
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safety goggles
non-latex gloves
preserved fetal pig
antibacterial soap
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scalpel
ruler
clear bag
dissecting pins
Procedure:
Part 1: External Anatomy
1. The fetal pig has four main body segments: the head,
neck, trunk, and tail. You will also be able to identify four
appendages and an umbilical cord 
2. Use a string about ~120 cm to measure your pig from
the tip of its snout to the base of its tail. Lay the pig flat on
the dissection tray and stretch the string between the nose
and the tail. Measure the section of string against a ruler
and match your measurement in Table 1 to determine the
age of your pig 
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dissecting tray
string
scissors
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dissecting microscope
blunt probe
paper towel
Table 1: Relationship of fetal Pig Length to Age in Utero
Length of String (cm)
0-10
10-20
20-30
40-50
100
150
200
300
Age of Pig (in days)
20
30-35
45-50
55
70
80
100
120
Use the same string to tie the pig later on. 
3. Place the fetal pig on its back (dorsal surface) and locate
the pairs of nipples along the ventral surface. Both male
and female fetal, pigs have these nipples. Notice the
umbilical cord. What is the function of the umbilical cord?
How many blood vessels do you see within the umbilical
cord? (see if you can identify the 2 umbilical arteries (red)
and one umbilical vein (blue). 
Figure 1: Body segments and planes of section in a fetal pig
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4. Sex determination:
a. Use the diagrams to determine the sex of your pig. In females, the urogenital opening is located slightly ventral to the
anus. A small, spiked tissue often called the genital papilla projects from the urogenital opening. See Figure 2 (a). 
b. In males, the scrotum containing the testes can be located just ventral to the anus. The urogenital opening of the
male is found immediately posterior to the umbilical cord. See Figure 2 (b). What is the sex of your pig? 
Figure 2: a) Female pig
b) male pig
5. Examine the feet of the fetal pig. Indicate the position and the number of toes. 
6. Examine the head of your fetal pig. The flaps of skin surrounding the ear are called pinnae. The fetal pig has a snout
and nostrils. Examine the chin of your fetal pig. Do you notice any hair? Does your fetal pig have eyelashes? Does
your fetal pig have a tongue? 
Part 2: Internal Anatomy
A- Abdominal Cavity and the Organs of Digestion
Examine various organs as they become visible. It is important to follow the directions carefully and to only remove
those organs that you are specifically asked to remove. Proceed carefully. Start with superficial incisions first and then to
follow those with deeper incisions to avoid mistake.
7. Exposing the ventral surface: With the pig still on its dorsal surface, attach
one piece of string to each of the pig’s ankles, pull string underneath the
dissecting tray to tie the opposite wrist. Repeat the procedure for the other
wrist. Making sure the pig is well secure 
To effectively expose the inner organs of your fetal pig, make five incisions.
1st incision
2nd incision
3rd incision
4th incision
cutting the ventral surface: (Hint: because the pig may be rubbery from being preserved, sharp
dissecting scissors are better than a scalpel for this incision.) Make a 10-15 cm incision just in front of
the umbilical cord and cut toward the head. Follow incision 1 in Figure 3. Sketch the incision first using
a black marker on the surface of the fetal pig. This will ensure the accuracy of your incisions. 
cutting toward the posterior surface. Use a scalpel to make an incision toward the posterior of the pig.
Follow incision 2 in Figure 3. 
cutting toward the lateral surface. Use scissors to make lateral incisions following incision 3 in Figure
3. 
cutting toward the posterior portion of the abdominal cavity. Use a scalpel to make incisions following
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incision 4 in Figure 3. 
5th incision
cutting between the thoracic and abdominal cavities. Use scissors to make an incision starting at the
midline, and extend the incision laterally on both sides of the pig. Follow incision 5 in Figure 3. This
incision runs parallel to the diaphragm and separates the thoracic and abdominal cavities. Hint: You
may want to feel for the ribs while making this incision 
Figure 3: Incisions for dissection of a fetal pig
Figure 4: The organs of digestion
8. Exposing the abdominal cavity:
- Pull apart the flaps at incision 5 best exposes the abdominal cavity. 
- Notice the layer of connective tissue called the peritoneum that holds the abdominal organs in place. You may
need to tease this layer away before examining the internal organs. The posterior portion of the abdominal cavity is best
viewed when the flaps on incision 4 are pulled apart and secured by pins. Refer to Figure 4 for the digestive organs. 
9. Locating the liver and the gallbladder (accessory organs of the digestive system):
Locate the liver. The liver appears a dark red or brown colour, because it is engorged with blood. The liver contains 20%
of the total blood supply in the fetal pig’s body at any given time. 
The gallbladder is underneath the liver. 
Look carefully to see the thin duct that connects the gallbladder to the small intestine. Which portion of the small
intestine does the gallbladder connect to? 
10. Locating the stomach: Beneath the liver, on the left side of the fetal pig, is the stomach, which is normally a hollow
organ. The anterior portion of the stomach is joined to the esophagus. The posterior junction is attached to the first part
of the small intestine, called the duodenum.
With your dissection tool, try to lift the small intestine. What do you notice? A thin, transparent film covers the small
intestine. This is called the mesentery. This film or layer of connective tissue is around other organs. What is the
advantage of having such a film? Observe the blood vessels running in the mesentery. 
11. Locating the pancreas: The pancreas is located toward the back wall of the abdominal cavity. It is a grainy, fingershaped gland that is typically creamy white in colour. It is best reached by lifting the junction between the stomach and
the small intestine. As an accessory organ in digestion, what vital substances does the pancreas provide? 
12. Locating the spleen: Look toward the left side of the fetal pig to see the spleen, found near the outer curvature of
the stomach. What is its function? 
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13. Remove the stomach by cuts at the junctions with the esophagus and the small intestine. Cut along the midline of
the stomach, rinse the stomach with water, and examine it under the dissecting microscope/magnifying glass. Observe
the lining of the stomach. What is the folds of the stomach called? Identify the cardiac and pyloric sphincters 
14. Locating the small and large intestines: Carefully use your scissors to snip away the mesentery tissue. Unravel the
small intestine. Locate the large intestine and compare its structure and length with those of the small intestine. How is
the small intestine different from the large intestine? How long is your pig’s small intestine (measure with a ruler and
rinse the ruler)? Locate the cecum 
B- Thoracic Cavity and the Organs of Respiration and Circulation
15. Exposing the thoracic cavity: Using dissecting pins, fold back and pin the flaps of skin that cover the thoracic cavity.
The thoracic cavity is the area between incisions 3 and 5. Refer to Figure 5 for the heart and major blood vessels.
16. Locating the heart: The heart is found between the two lungs and is protected by the rib cage. In the adult human,
gaining access to the heart is very difficult, and
involves the sawing of the sternum and
spreading of the ribs. In the fetal pig, one does
not need much force to access the heart. In fact,
simple scissors are enough for this task. Can you
explain this? 
17. A thin and transparent film called the
pericardium, similar to the mesentery of the
small intestine, surrounds the heart. Use forceps
to remove the pericardial membrane that
encases the heart. 
18. Discovering the four chambers of the heart: Do a laptop cut (see diagram on the right) of the heart but DO NOT cut
the heart out of the pig 
Using your blunt probe, locate the right and left atria as well as right and left ventricles. 
Look at the thickness of the left and right ventricles. Compare the size of the wall of a ventricle and an atrium. What do
you notice? Why does the left ventricle contain more muscle than the right ventricle?
19. Notice several vessels entering
the left atrium. These are the
pulmonary veins from the lungs. 
20. Find the aorta coming off the
left ventricle and the pulmonary
trunk (= pulmonary artery) arising
from the right ventricle
Deoxygenated blood from the body
enters the heart here. 
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21. Locating each of the major vessels of the heart. 
Insert the probes from your kit to the opening of these blood vessels. It will help you see the vessels more clearly.
inferior vena cava:
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runs from the liver and lower part of the body to the right side of the heart; empties into the
right atrium.
superior vena cava:
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runs from the upper body of the pig to the right side of the heart; empties into the right
atrium.
pulmonary trunk
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starts at the right ventricle; transports deoxygenated blood to the lungs
aorta:
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the largest artery in the circulatory system; starts at the left ventricle; branches to transport
blood to all major organs. Passes through the thoracic and abdominal cavities.
aortic arch
 the part of the aorta that arises from the left ventricle. Two major vessels come from the
aortic arch; the brachiocephalic trunk splits to send vessels to the right forelimb and the
head, the left subclavian artery supplies the left forelimb.
22. Review the flow of blood through the heart. The pulmonary circulation begins at the right atrium; blood flows to
the right ventricle, pulmonary trunk and pulmonary arteries and then to the lungs. The blood returns to the left atrium
by way of the pulmonary veins. The systemic circulation begins at the left atrium; blood flows to the left ventricle, aorta,
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and to all systems of the body. Blood returns to the heart by way of the superior and inferior venae cavae, which enter
the heart at the right atrium.
23. Remove the heart from the thoracic cavity. You may need to tease away any connective tissue. Hold the heart in
your hand and orient it, as it would appear in the fetal pig. Note the large vessel that traverses the ventral surface of the
heart. This is the coronary artery and it provides oxygenated blood to the heart itself. 
24. The dorsal surface of the heart. Turn the heart over and
observe the dorsal surface. Refer to Figure 6 and observe
the entry of the venae cavae and pulmonary veins into the
right and left atria. 
25. Locating the lungs: close to the heart. They oxygenate
the blood received from the right ventricle via the
pulmonary arteries, and deliver oxygenated blood back to
the left atrium via the pulmonary veins. The lungs are
relatively large because the bronchial tree is contained
within them. Do you notice any difference in the size of
the two lungs? 
26. Locate the spongy lungs on either side of the heart and
the trachea leading into the lungs. Why do the lungs feel
spongy? 
27. Place your index finger on the trachea and push downward. Describe what happens. What function do the cartilage
rings of the trachea serve? Where is the esophagus in relation to the trachea? 
Open up the neck to expose the larynx. 
End of Dissection Manual
Online pre-lab/ review pig dissection resources
1. https://www.youtube.com/watch?v=ZWYpnLtXQrg (part 1)
2. https://www.youtube.com/watch?v=eCNxnBbfkVs (part 2)
3. https://www.youtube.com/watch?v=Hdijzf6frgQ (part 3)
4. https://www.youtube.com/watch?v=csP2LJ1yy9g
5. http://www.biologycorner.com/myimages/fetal-pig-dissection/
Pig dissection word list
Digestive System
Tongue
Liver
Duodenum
Jejunum
Ileum
Pharynx
Small
Intestine
Gall
bladder
Circulatory system
Atria
Pulmonary Artery
Miscellaneous: Spleen
Salivary
Glands
Pancreas
Pyloric
Sphincter
Cardiac
Sphincter
Respiratory system
Esophagus
Mesentery
Rectum
Anus
Large Intestine
(colon)
Cecum
Ventricles
Pericardium
Aorta and Aortic Arch
mesentery
peritoneum
nipple
Diaphragm
Trachea
Cartilaginous
rings
Bronchial
tubes
Coronary Arteries
Umbilical arteries and vein
Larynx
Epiglottis
Pharynx
Lungs
Anterior and Posterior Vena Cava
pinnae
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SBI3U/C – Animals: Structure and Function Unit
Date: _____________________
Dissection and Anatomy of a Vertebrate Mammal: The Fetal Pig
JOURNAL LOG
Period: _______
Dissection Kit #: _________
Names of Group Members:
Group #: _________
Sink #: _________
1.
Role you play
2.
Surgeon
3.
Instructor (i.e. Boss)
Assistant (i.e. Manager)
Ensure you answer the questions below AS you perform the dissection.
Submit one copy per group at the end of each period.
Marks Allocation
Marks
Allotted
Reason(s) for Deductions
Journal Log
5
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Performing, clean-up, etc.
3
Quality of the dissection (clean cuts, using
correct tools, tissues not destroyed, etc)
10
Criteria
Your Mark
18
Inquiry
Total
Questions:
1. What is the sex of your group’s fetal pig?
Male
or
female
2. What is the approximate age of your pig? ______________________
3. a) What is the function of the umbilical cord?
b) How many blood vessels do you see within the umbilical cord? _________________
4. a) Do you notice any hair?
Yes
or
No
b) Does your fetal pig have eyelashes?
Yes
or
No
c) Does your fetal pig have a tongue?
Yes
or
No
5. Which portion of the small intestine does the gallbladder connect to? _____________________________________
6. Why are liver, gall bladder and pancreas collectively called accessory organs?
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7. What is the function of the peritoneum? Where is it found?
8. What is the advantage of having such a film (mesentery)? Where is it found?
9. As an accessory organ in digestion, what vital substances
does the pancreas provide?
10. What is the function of the spleen?
11. What do you notice when you observe the inner lining of the stomach under the dissecting microscope/magnifying
glass?
12. a) How is the small intestine different from the large
intestine?
b) What is the length of the unraveled small intestine?
______________
13. Do you notice any difference in the size of the two
lungs? Explain.
14. Why do the lungs feel spongy?
15. What function do the cartilage rings of the trachea
serve?
16. Where is the esophagus in relation to the trachea?
17. What do you notice between the sizes of the walls of the
atria and the ventricles?
18. Why does the left ventricle contain more muscle than
the right ventricle?
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19. Indicate in the following table whether the blood should be O2-rich (i.e. oxygenated) or O2- poor (i.e. deoxygenated)
at the locations specified by #(4m)
7.
8.
9.
10.
11. O2- rich (oxygenated)
12.
13.
14.
15.
16.
18a. What chambers of the heart receive blood from the body, ventricles or atria? ___________
b. What chambers of the heart pump blood out of the heart, ventricles or atria? ___________
c. Which blood vessel brings oxygen poor blood to the heart from the rest of the body?
___________________________________
d. Which blood vessel takes blood from the heart and sends it to the lungs? ________________________
e. Which blood vessel takes oxygen-rich blood from the lungs and brings it back to the heart?
________________________________________________________
f. Which blood vessel sends oxygen-rich blood from the heart to the rest of the body?
________________________________________________________
g. How do the valves control the flow of blood through the heart? ___________________
____________________________________________________________
h. Blood from the rest of the body enters the heart via ______________________ and ___________________
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