This document outlines the procedures and objectives for a three-day fetal pig dissection lab for 7th grade students. On day one, students will examine the pig's external anatomy by locating features like toes, ears, and sex organs. Day two focuses on internal anatomy with students identifying organs like the liver, stomach, intestines, and spleen. Day three examines the circulatory system where students will locate the four-chambered heart and related vessels. Safety protocols are reviewed, such as wearing protective equipment and cleaning materials.

1. 7th grade final exam
Pig dissection
Mrs. Riesterer
1st hour
2013

2. Safety & Reminders
• No horseplay in the lab
• Always wear gloves, if yours
gets a hole get a
replacement
• Clean up your area and
disinfect everything that is
in your area (including the
tools you used)
• Place your pig in a plastic
(sealed) bag and label it
with your group/pigs name
• Wear lab apron and eye
goggles at all times
• Make sure you have the
following in your lab station
daily:
– Dissecting pan
– Dissecting scalpel
– Dissecting scissors
– Dissecting pins
– Dissecting forceps
– Dissecting probe
– Measuring tape
– Your pig

3. Day 1 – external anatomy
» Ventral surface
» Lateral surface
» Dorsal surface
» Anterior end
» Posterior end
• Obtain a fetal pig and rinse off the excess
preservatives by holding it under water.
• Lay pig on its side in the dissecting pan and
locate the:

4. Day 1 – external anatomy
• A fetal pig is a pig that has not been born yet,
but its approximate age since conception can
be measured by measuring its length.
– Measure from the tip of the pigs snout to the base
of the pigs tail.
– Use the chart that is on the board to figure out
how old your pig is

5. • Examine the pigs head. Locate the following:
– External nostrils
– External ears (pinnae)
• Look at the pigs appendenages
– How many toes does the pig have?
– Is there a difference between the front and the hind
hooves
• Observe the eyes of the pig – carefully remove the
eyelid so that you can view the eye underneath
– Does it seem well developed
– Do you think pigs are born with their eyes open or shut?
Day 1 – external anatomy

6. • Locate the umbilical cord. Use the dissecting
scissors to cut across the cord 1 cm from the
body.
• Determine the sex of your pig
– Locate the urogenital opening through which
wastes and reproductive cells pass through.
• Males – the opening is on the ventral side of the pig
just posterior to the umbilical cord.
• Females – the opening is ventral to the anus
Day 1 – external anatomy

7. • Carefully lay the pig on one side in your
dissecting pan and cut away the skin from the
side of the face and upper neck to expose the
following (label them on your handout):
» Masseter muscle (muscle that works the jaw)
» Lymph nodes
» Salivary glands
• With your scissors, make a 3 cm incision in
each corner of the pig’s mouth – your incision
should extend posteriorly through the jaw.
Day 1 – external anatomy

8. • Spread the jaws and examine the tongue
• Notice the palate on the roof of the mouth
– Anterior part is the hard palate
– Posterior part is the soft palate
• Notice the taste buds (sensory papillae) on the
side of the tongue
• Locate the esophagus at the back of the mouth
• Feel the edge of the pigs mouth. Are there
teeth? Are humans born with teeth?
Day 1 – external anatomy

9. • Clean up your materials and lab stations. Get
a plastic zip-lock bag from Mrs. Riesterer and
label it with your pigs name.
• Wrap the pig in damp paper towels and put it
in a zip-lock bag.
• Return the equipment (once cleaned and
disinfected) to the proper location.
• Wash your hands thoroughly with soap and
water.
Day 1 – wrap up

10. • Place the pig in the dissecting pan, ventral side
up
• Tie a string securely around a front limb. Run
the string under the tray, pull it tight & tie it to
the other front limb. Now repeat with the
hind limbs.
Day 2 – internal anatomy

11. Day 2 – internal anatomy
• Use your scissors to cut
through the skin and the
muscle according to the
diagram.
• Do NOT remove the
umbilical cord.
• Be careful not to cut too
deep.
• You may need to “drain”
your pig to remove any
preservatives that are still
inside the pig, but make
sure no organs fall out.

12. • Locating organs:
– The liver (brownish color), count the number of
lobes.
– The esophagus (tube-like), joins the mouth to the
stomach
– The stomach – located beneath the liver
• Carefully cut along the outer curve of the stomach –
note the texture of the inner walls.
Day 2 – internal anatomy

13. • Identifying more organs:
– Small intestine – connected to the stomach
• Carefully cut through the small intestine (at the small end only)
and uncoil it.
• Measure its length and record that on your data sheet
• With your scissors cut a 3cm piece of the lower small intestine.
Cut it open and rinse it out.
– Large intestine – follow the small intestine until it reaches
the wider, looped intestine.
• Unwind the large intestine and measure its length.
• how do the length of the 2 intestines compare to each other? Is
this what you expected from what you learned in class.
• Notice that the large intestine leads to the rectum.
Day 2 – internal anatomy

14. • Locate more organs
– Locate the thin, white pancreas beneath the
stomach.
– Between the lobes of the liver, find the small
greenish-brown gall bladder.
– Find the spleen, a long, reddish-brown organ
wrapped around the stomach. Remember the
spleen filters out old red blood cells and produces
new ones for the fetus.
Day 2 – internal anatomy

15. • Clean up your materials and lab stations. Get a
plastic zip-lock bag from Mrs. Riesterer and label
it with your pigs name.
• Wrap the pig in damp paper towels and put it in a
zip-lock bag.
• Return the equipment (once cleaned and
disinfected) to the proper location.
• Wash your hands thoroughly with soap and
water.
• Complete the organ fill in sheet for homework
Day 2 – wrap up

16. • Locate the heart – notice that the pig as a four
chamber heart just like all other mammals.
– The right side of the heart pumps blood to the
lungs, while the left side of the heart pumps blood
to the rest of the body
– Each side of the heart has an upper and a lower
chamber. Upper chambers are called atria and
receive blood, while the lower chambers are
called ventricles and they pump blood out of the
heart.
Day 3 – circulatory system

17. • Find the pulmonary artery which leaves the
right ventricle. After birth, this vessel carries
blood to the lung.
• Find the pulmonary veins that enter the left
atrium. After birth, these vessels carry blood
from the lungs to the heart.
• Identify the aorta, a large artery that
transports blood from the left ventricle.
Day 3 – circulatory system

18. • Remove the heart by severing the blood
vessels attached to it.
• Hold the dorsal and ventricle surfaces of the
heart with your thumb and forefinger and rest
the ventricles on your dissecting pan. With a
scalpel, cut the heart into dorsal and ventricle
halves.
• CAUTION: the scalpel is very sharp. Use it
carefully and always cut away from yourself.
Day 3 – circulatory system

19. • Remove any material inside the heart and expose
the walls of the atria and the ventricles.
• Study the internal features of these chambers
and note where vessels leave or enter each
chamber. Locate the valves between each atrium
and ventricle. These structures prevent blood
from flowing backward in the heart.
Day 3 – circulatory system

20. • Clean up your materials and lab stations. Get a
plastic zip-lock bag from Mrs. Riesterer and label
it with your pigs name.
• Wrap the pig in damp paper towels and put it in a
zip-lock bag.
• Return the equipment (once cleaned and
disinfected) to the proper location.
• Wash your hands thoroughly with soap and
water.
• Complete the heart fill in sheet for homework
Day 3 – wrap up

21. References
Martin, Phillip. Free Clip Art. N.p., n.d. Web. 7 May 2013.
<http://animals.phillipmartin.info/animal_pig2.html>.
Muskopf, Shannan. The Biology Corner. N.p., 2001. Web. 6 May 2013.
<http://www.biologycorner.com>.