Download Pig Dissection Lab

Fetal Pig Dissection:
Page 1
External Anatomy
1. Determine the sex of your pig by looking for the urogenital opening. On females, this opening is located
near the anus. On males, the opening is located near the umbilical cord.
If your pig is female, you should also note that urogenital papilla is present near the genital opening. Males
do not have urogenital papilla.
Both males and females have rows of nipples, and the umbilical cord will be present in both.
Is your pig male or female? ___________
2. Make sure you are familiar with terms of reference: anterior (toward the head), posterior (toward the
anus), dorsal (back), ventral (underneath side). In addition, you'll need to know the following terms
Medial: toward the midline or middle of the body
Lateral: toward the outside of the body
Proximal: close to a point of reference
Distal: farther from a point of reference
3. Observe the toes of the pig. How many toes are on the feet? ___________________
Do they have an odd or even number of toes? _________________
4. 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? __________
As you identify all of the parts of the pig (bold words throughout the packet) put a check on each
line or in each box after everyone in your group has seen this part.
5. 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 _____masseter muscle that works the jaw, ____lymph nodes, and
_____salivary glands, (put a check on the line after you have located it each bold word). The salivary
glands look kind of like chewing gum, and are often lost if you cut too deeply.
6. Open the pig's mouth and locate the _____hard and _____soft palate on the roof of the mouth. Can you
feel your own hard and soft palates with your tongue? _______
Note the taste buds (also known as ______sensory papillae) on the side of the tongue. the edge of the
mouth for teeth. Does the fetal pig have teeth? ________ Are humans born with teeth? ___________
7. Examine the pharynx which is the cavity in the back of the mouth. To do this you will need to cut the
muscle tissue along the jaw and crack the jaw bone by carefully placing your thumbs inside the pigs mouth,
one on the soft palate and one on the tongue, pull apart until you hear it crack. The ______pharynx is the
junction of the _______esophagus (which carries food to the stomach) and the ______trachea (which
carries air to the lungs). Locate the _______epiglottis, a cone-shaped structure at the back of the mouth.
What is the function of the epiglottis? _____ ______________________________________
Pig Picture 1
Email Photo with Labels to [email protected]
Title: PigPic1-Per ___ Lab ___
Structures to Label: Epiglottis, Salivary glands, soft palate, hard palate, taste buds, pharynx
Digestive System
Page 2
In this activity, you will open the abdominal and thoracic cavity of the fetal pig and identify structures.
Remember, that to dissect means to "expose to view" - a careful dissection will make it easier for you to find
the organs and structures. Be sure to follow all directions.
The Incision: Place your fetal pig in the dissecting pan ventral side up. Use
string to "hog-tie" your pig so that the legs are spread eagle and not in
your way. Use scissors to cut through the skin and muscles according to
the diagram. Do not remove the umbilical cord. In the first section, you will
only examine the abdominal cavity (the area below the ribcage). Try not to
cut the inner organs while making the incision. After completing the cuts,
locate the _______umbilical vein that leads from the umbilical cord to the
liver. You will need to cut this vein in order to open up the abdominal
cavity. Pin the skin and muscle to the side so that the internal organs are
visible. Your pig may be filled with water and preservative, drain over the
sink if necessary and rinse organs.
Locate each of the following organs below, check the box when you
have located the structure.
1. Diaphragm. This muscle divides the thoracic and abdominal cavity and is located under the ribcage.
The diaphragm aids in breathing.
2. Liver. This structure is lobed and is the largest organ in the body. The liver is responsible for making
bile for digestion.
3. Gall bladder. This greenish organ is located underneath the liver; the bile duct attaches the gall
bladder to the duodenum. The gall bladder stores bile and sends it to the duodenum, via the bile duct.
4. Stomach. A pouch shaped organ that rests just underneath and to the pig's left. At the top of the
stomach, you'll find the esophagus. The stomach is responsible for churching and breaking down food.
5. The stomach leads to the small intestine, which is composed of the ___duodenum (straight portion
just after the stomach) and the____ ileum (curly part). The ileum is held together by ____mesentery
(thin clear tissue/ membrane). In the small intestine, further digestion occurs and nutrients are absorbed
through the arteries in the mesentery.
6. Pancreas: a bumpy organ, probably white in color, located along the underside of the stomach, a
______pancreatic duct leads to the duodenum. The pancreas makes insulin, which is necessary for
the proper uptake of sugars from the blood. It also makes many digestive enzymes
7. Spleen: a flattened organ that lies across the stomach and toward the extreme left side of the pig.
The spleen stores/breaks down red blood cells. It looks like a little tongue stuck to the stomach.
8. Large intestine: At the end of the ileum (small intestine), where it widens to become the large
intestine, a "dead-end" branch is visible. This is the cecum. The cecum helps the pig digest plant
material and is the beginning of the large intestine. (you can possibly see little appendix hanging off)
9. The large intestine can be traced to the ____rectum. The rectum lies toward the back of the pig and
will not be moveable. The rectum opens to the outside of the pig, or the _____anus. The large intestine
reabsorbs water from the digested food; any undigested food is stored in the rectum as feces.
Pig Picture 2
Email Photo with Labels to [email protected]
Title: PigPic2-Per# ___ Lab #___
Structures to Label: Diaphragm, gall bladder, liver, stomach, pancreas, spleen, large intestine, small
intestine
Carefully remove and examine each of the following structures:
Page 3
1. Remove the stomach by cutting it transversely (crosswise) across the esophagus and duodenum. Make a
longitudinal (lengthwise incision along the stomach so that you can open it and view the inside. There are
two important valves in the stomach: the ___cardiac sphincter (located at the anterior end) and the
____pyloric sphincter valve (located at the posterior) end. These valves open and close to allow food into
and out of the stomach. When the cardiac sphincter does not do its job, stomach acid bubbles up into the
esophagus causing ‘heart burn’.
2. Remove the small intestine and carefully cut the mesentery (clear membrane) so that the intestine can be
stretched and measured. Note the arteries located in the mesentery - called ______mesenteric arteries.
What is the length (in centimeters) of the small intestine? ______________ (optional, if time)
Urinary and Reproductive Systems
---Locate each of the structures below and check the box when you have found them. Make sure to view
both the male and female pig.
1. Lying on either side of the spine are two bean shaped organs: the kidneys. The kidneys are
responsible for removing harmful substances from the blood; these substances are excreted as
urine. Locate the ______kidneys. The tubes leading from the kidneys that carry urine are the
_____ureters. The ureters carry urine to the _____urinary bladder - located between the
umbilical vessels.
2. Lift the bladder to locate the ____urethra, the tube that carries urine out of the body.
Male
1. Find the ____scrotal sacs at the posterior end of the pig, ____testis are located in each sac.
Open the scrotal sac to locate the testis.
2. On each testis, find the coiled ______epididymis. Sperm cells produces in the testes pass
through the epididymis and into a tube called the _____vas deferens (in humans, a vasectomy
involves cutting this tube).
3. The vas deferens crosses over the ureter and enters the ___urethra, which leads to the
___penis. The penis will be located in the flap that has the umbilical cord. Cut away the skin to
reveal the penis.
Female
4. In the female pig, locate two bean shaped ____ovaries located just posterior to the kidneys.
5. The ovaries are connected to the _____fallopian tubes, which carry eggs from the ovaries to
the _____uterus. The uterus looks flat and wavy (scalloped). The uterus is dorsal to the urinary
bladder.
6. Trace the uterus to the ___vagina. The vagina will actually will appear as a continuation of the
uterus. The vagina and urethra open into a common area called the _____urogenital sinus.
Pig Picture 3
Email Photo with Labels to [email protected]
Title: PigPic3-Per# ___ Lab #___
Structures to Label: Kidney, Ureter, Bladder, Colon
Males: Testes, epididymis, and Vas Deferens
Females: Ovaries, fallopian tubes, uterus, Label the diagrams
Label the diagrams (make sure you see a boy and girl pig)
Page 4
Dissection of the Thoracic Cavity Circulatory/
Respiratory System
You may need to cut through the pig's sternum and
expose the chest cavity (thoracic cavity) to view. See the
diagram to make the incisions. You will need to cut all
the way up into the pig's neck, almost to the chin and
open the thoracic cavity. Identify each of the following
organs.
1. Find the ____diaphragm again. Remember that the diaphragm separates the abdominal cavity
from the thoracic cavity and it aids in breathing.
2. Remove the ____pericardium, which is a membrane that surrounds the heart. This membrane is
also located over many of the organs and can get in the way of your view.
3. The structures visible on the heart are the left and right ___atrium, the right and left
____ventricles (which has two chambers but the separation is not visible from the outside), and the
large Aorta - a vessel which leaves the heart. (more on the heart later)
4. Push the heart to the side to locate two spongy ____lungs located to the left and right side. The
lungs are connected to ____bronchial tubes which connect to the _____trachea (forming a Y). If
you are careful and do not damage the bronchial tubes you can use a straw to inflate the lungs.
5. The ____trachea is easy to identify due to the ____cartilaginous rings, which help keep it from
collapsing as the animal inhales and exhales. The trachea should be located behind the heart and
liver and near the esophagus, but note that the esophagus and trachea are separate tubes.
6. Lying ventral to the trachea, locate the pinkish-brown, V shaped structure called the ____thyroid
gland. This gland secretes hormones that control growth and metabolism.
7. At the anterior end (toward head) of the trachea, you can find the hard light colored ____larynx
(or voice box). The larynx allows the pig to produce sounds - grunts and oinks.
Pig Picture 4
Email Photo with Labels to [email protected]
Title: PigPic4-Per# ___ Lab #___
Structures to Label: Thyroid, Larynx, Thymus gland, Trachea, Aorta, Ribs, Lungs, L. Atrium, R.
Atrium, L. Ventricle, R. Ventricle
Pig Structures
Identify each structure on the diagram. For the test: make sure you know the function of each part and what
body system it is a part of.
1.
9.
2.
3.
10.
4.
5.
11.
12.
6.
13.
7.
14.
8.
15.