2. Start date: 4/5/12
End date: 4/6/12
Project members: Naheen, Kyle, Mesha, Amna, Sandhya
Teacher’s name: Mr. Green
Background Information:
The excretory system regulates the chemical composition of body fluids by removing metabolic wastes
and maintaining the proper amount of water, salts, and nutrients. Nitrogen wastes are a by product of
protein metabolism. The urinary system is made up of the kidneys, ureters, bladder, and urethra. The
nephron is the kidney’s functional unit. Water is filtered from the blood and collected as urine in the
kidney. Urine leaves the kidney by ureters and collects in the bladder. The bladder can store urine until
it leaves through the urethra. The nephron consists of a bowman’s capsule, the glomerulus, and a long
renal tube. Blood flows into the kidney through the renal artery, which causes water and solutes to
filter through the capsule. After the glomerular is done with the filtration, water and needed molecules
are sent back into the blood and ions and wastes are sent into a distal tubule.
In this investigation, we will discover how the excretory system can be observed in fetal pigs.

3. Purpose: How can we observe the excretory system of the human body in fetal pigs?
Hypothesis: If we believe that the excretory system operates similarly in fetal pigs and humans, than we should be
able to accurately observe the organs of this system and how they function in our bodies.
Materials:
•Fetal pig
•Dissecting tools (scalpel, scissors, probe)
•Disposable gloves
•Camera
Procedure:
1.) Place the pig on its back in the dissecting pan. Tie a piece of string around the "wrist" of one of the front legs. Run the string
under the width of the dissecting pan and tie it around the wrist of the other front leg. Pull the string fairly tight so that the legs
are spread apart. Secure the hind legs in the same way.
2.) Being making incisions based on the image provided in your lab sheet. Pull apart the flaps of the body between the front and
hind legs. Carefully pull up the flap with the umbilical cord a slight way. Cut off the umbilical vein.
3.) Rinse out the abdominal cavity of your specimen. Carefully push its organs aside until you see two bean shaped organs
(kidneys).
4.) After identifying the kidneys, trace the ureter from the kidney to bladder. Identify the urethra, which carries urine outside of
the body.

4. The large intestine breaks down wastes, which is later excreted.
(Fetal pigs send this waste to their mothers through the umbilical cord)

5. Analysis:
During this lab, I was able to observe the excretory system of a fetal pig. After wastes are filtered from
blood in each kidney, urine leaves the kidneys through ureters. From this location, the urine is sent to
the bladder. Here, it is stored and eventually leaves through the urethra. This fetal pig has not made use
of its kidneys, ureter, urinary bladder, or urethra. This is because since the animal was never born, it
used its mother’s umbilical cord in order to deposit its wastes. When you cut open a kidney, the lines
that you see are the many blood vessels that filter out blood during filtration. The nephron are located
in the medulla and cortex of the kidney, and appear like a group of bundled capillaries.
The large intestine, or the colon, is the last part of the excretory system observed. It is the organ that
removes solid waste from the body. Its function is not only to remove solid waste but to collect water
from the waste that can be reused. It is part of the alimentary canal. The waste is stored in the rectum
until it is released through the anus.

6. Conclusion:
In conclusion, my hypothesis was correct. I was able to accurately observe the human excretory system
in a fetal pig.
Fetal pigs are often used in classroom dissections. These mammals have similar hair, organ systems,
metabolic levels, and body forms as humans. Their soft tissue and underdeveloped bones (cartilage)
make them easier to dissect than other organisms. The fetal pig does not use their excretory system. All
of their wastes are transferred by the umbilical cord to the mother, who excretes the wastes.
From this lab, I was able to learn that dissection is a work of art. It is important to make the correct
incisions and restrain from damaging important organs and tissue. This lab has helped prepare me for
future dissections.