Examining the Fetal Pig
Part One: External Anatomy and Beginning the Dissection
Purpose:
Materials:
To study a mammal having similar anatomy to that of a human.
To learn what features separate mammals from other types of animals.
To compare the features of mammals to the other animal groups we dissected.
To learn the general guidelines for the fetal pig dissection.
1 fetal pig
1 gallon-sized Ziploc bag
1 dissecting tray
forceps
probes
scissors
scalpel or razor blade
gloves
Introduction:
The fetal pig has been chosen as a dissection specimen to acquaint you with the structure of
the mammalian body. Our biology course provides information and concepts related to human
anatomy and physiology. Being a mammal, the anatomy of the pig is very similar to that of a
Human. The fetal pig dissection should give you a good idea of how your organs are arranged
and function.
Mammals differ widely in body structure. This is evident when considering that pigs,
humans, bats and whales are all mammals. Even though body forms differ, members of Class
Mammalia share certain common characteristics including:
 A body covered with hair
 Young nourished with milk from the mother’s mammary glands through teats(nipples)
 A diaphragm (muscle for breathing) that separates the thoracic cavity from the abdominal
cavity
 A four chambered heart as part of a closed circulatory system
 Is endothermic(warm blooded) to maintain a constant body temperature
Introduction to External Anatomy:
The period of development (gestation) for a pig is 112-120 days. When the female pig
gives birth, there are usually seven to twelve piglets in a litter. The pig that you are dissecting
was not yet born (hence the name fetal. A fetus is a developing embryo that has acquired the
mammalian form). These pigs were not bred to supply us with lab specimens. When pregnant
female are sent to market, rather than discarding the fetuses, they are saved for dissection.
The age of the fetal pig can be determined by measuring its length from tip of nose to
beginning of the tail…
 220 mm pig is about 100 days old
 240mm pig is about 105 days old
 260 mm pig is about 110 day old
 280 mm pig is about 115 days old
 300 mm pig is about 120 days old
The sex of the pig is easy to determine. The male pigs have two sac-like swellings located just
posterior to the hind legs. These are the scrotal sacs containing the testes. The testes produce the
sperm cells in the adult male as well as serve to produce and release male sex hormones. In the
fetal pig the scrotal sacs may not be entirely obvious. The urogenital opening, however, is easily
seen upon close inspection. In the male, this small opening is located just behind the umbilical
cord on the belly of the pig. The penis lies under the skin just behind the urogenital opening so it
cannot be seen. It is a muscular tube through which sperm cells are released during copulation
and through which urine passes during urination. In female pigs, the small urogenital opening is
located just below the anus( unlike the male in which it is right behind the umbilical cord). Also
under the tail is a small, fleshy, triangular projection called the genital papilla. The male does not
have a genital papilla.
During development of the fetus, the blood of the mother and the blood of the fetus do not
mix. Actually, the placenta is attached to the wall of the mother’s uterus and at the placenta,
materials from the mother’s blood and fetuses blood are exchanged. Nutrients that the fetus need
will diffuse from the blood vessels in the mother’s uterus into the fetal blood found in the
placenta. Likewise, waste from the fetuses blood will enter the mother’s blood where she will
eventually get rid of them. The nutrients that enter the placenta from the uterus will be carried to
the fetus through the umbilical cord. Part of the umbilical cord still remains on the fetal pig that
you are dissecting. In a cross section of the umbilical cord, two thick walled umbilical arteries
can be seen. The arteries carry blood from the fetus to the placenta, where they exchange waste
for nutrients with the mother’s blood. Also in the umbilical cord is a larger thin walled vessel that
may be flattened called the umbilical vein. The vein carries blood back from the placenta to the
fetus. Finally there is the allantoic duct which is extension of the fetal urinary bladder into the
umbilical cord.
Procedure:
1. Obtain two 18 inch pieces of string and tie them around the pigs legs as demonstrated by
your instructor.
2. Using the characteristics of mammals mentioned in the introduction, list all of the
characteristics that you can see on your pig.
3. Locate the umbilical cord and observe the four tubes described above.
4. Cut the jaw bones as demonstrated by your instructor. Open the mouth and find the
tongue and teeth. Count how many teeth are visible in your pig. Note the hard palate,
which is the bony, upper roof of the mouth cavity. It has a ridged appearance. The soft
palate is a continuation of the hard palate that extends toward the back of the throat(it does
not have bone beneath it).
5. Locate the lips and external nares (nostrils).
6. Locate the external ears.
Beginning the Dissection:
1. Throughout the dissection it is important that you read the directions carefully and only
do what the directions tell you to do. Dissecting should be done carefully and slowly, by
making the cuts when instructed to do so, and by picking away the connective tissue to
make the organs more visible.
2. Never cut out any organs unless specifically directed to do so.
3. Slowly make incisions #1-5 as shown below. Pull up on the body wall and using the
scissors, cut all the way through the body wall until the preservative starts to leak from the
cut. Do not cut too deeply. Keep the scissors parallel to the body wall to avoid cutting into
organs.
4. You may pull on the umbilical cord to remove this ventral flap back toward the leg, but
you may have to cut the umbilical vein that extends to the liver to do so.
5. Rinse your tray and pig in the sink to clean any excess fluid that may have come out during
the dissection.
6. If there is not enough time to continue you will be given a Ziploc bag to protect your pig
until the dissection is completed.
Examining the Fetal Pig
Part Two: The Digestive System
Purpose:
To study a mammal having anatomy similar to that of a human
To compare the features of mammals to the other animal groups we dissected
To examine the specialized areas of the alimentary canal
Materials per Lab Station:
1 fetal pig
1 gallon-sized Ziploc bag
1 dissecting tray
gloves
probes
scissors
forceps
razor blade
Introduction:
The digestive system consists of many organs working together for the major purpose of
digesting food. Digestion is the process of breaking down large organic biomolecules into their
building blocks. The purpose for this is two-fold. By breaking down the molecules they will be
small enough to be absorbed into the bloodstream where the cells of the organism can use them.
Also, if one stops to consider, an animal's food was once another organism. The food molecules
are really the biomolecules once used by the previous organism. By digesting these molecules
into their building blocks, the animal can use some of these building blocks to construct its own
biomolecules. An animal eats not only to get molecules that can supply energy, but also to get
molecules from which it can make its own unique molecules.
The digestive system can be divided into two parts. The alimentary canal is the "food
tube" through which the ingested food actually travels. Food normally travels only one way
through an alimentary canal, with different regions of the canal being specialized to do different
jobs. The opening through which food is taken into the alimentary canal is the mouth, and the
opening through which the undigested materials leave the alimentary canal is the anus. While all
of the organisms we have dissected have alimentary canals, not all animals do. Many simple
animals found in the ocean, for instance, have a single digestive pouch in which digestion occurs.
These digestive pouches only have one opening, so food enters and wastes leave through the
same opening. These digestive pouches are not as advanced as alimentary canals because they
don't allow for regions to become specialized, and there is not one-way flow of food. Since the
digestive pouches only have one opening when wastes are expelled through it, any food just eaten
will be expelled as well. This is an obvious disadvantage.
The second part of the digestive system contains all of the accessory organs. These are
organs that are important for digestion, but do not actually have the food pass through them. The
best examples of accessory organs are the many glands that make digestive enzymes and juices
that are released into the alimentary canal. Examples of accessory organs include salivary glands,
the liver, pancreas, etc.
Introduction to the Alimentary Canal
The alimentary canal begins with the mouth cavity. It is in this chamber that digestion
begins. The teeth, tongue, and hard palate all work together to begin breaking the food down
mechanically. In other words, physical force is used to break down the food. This type of
digestion is called mechanical digestion. Mechanical digestion helps increase the surface area of
food particles so that enzymes will have more places to react. Mechanical digestion does not
break individual molecules apart, and does not break the food down enough to be absorbed into
the bloodstream. After the food has been crushed and formed into a mass by the tongue, it is
swallowed. The food passes to the back of the throat (pharynx) where the food then enters the
esophagus. The pharynx also contains the opening to the windpipe that carries air to the lungs.
A flap of tissue called the epiglottis covers the opening of the windpipe during swallowing to
prevent food or liquid from entering the lungs by accident. The esophagus is a muscular tube that
will pass food to the stomach. The food travels through the esophagus and the rest of the
alimentary canal by peristalsis. Peristalsis is the rhythmic contractions of smooth muscles in the
walls of the esophagus (and the organs following the esophagus) that push the food along.
The stomach is a large saclike organ that lies dorsal to the liver in the abdominal cavity.
The stomach stores food that has been eaten and will pass it on to the next organ, the small
intestine. The stomach does not just store the food however. It mechanically digests the food by
a muscular churning action. It also begins the chemical digestion of proteins by use of the
enzyme, pepsin, found in the gastric juice. Chemical digestion is the use of enzymes and other
chemicals to break food into smaller particles. It is chemical digestion that breaks the food into
particles small enough to be absorbed. Where the esophagus joins the stomach is the cardiac
sphincter. A sphincter is a circular muscle that will close off a tube or opening when the muscle
contracts. The cardiac sphincter closes when the stomach churns, preventing the acidic stomach
contents from flowing back up the esophagus. At the end of the stomach where it joins the small
intestine is another sphincter, the pyloric sphincter. This sphincter also closes off the stomach
while it is churning, but this sphincter also regulates how much food enters the small intestine at a
time. While the food may be eaten quickly by an animal, only small portions from the stomach
are allowed to enter the small intestine at a time. When performing the dissection, you will be
asked to cut into the stomach. When doing this you will notice many folds or ridges that run the
length of the stomach. These folds allow the stomach to expand when it is filled with food.
The organ that follows the stomach in the alimentary canal is the small intestine. This is
arguably the most important organ of the alimentary canal, for it is here that most chemical
digestion takes place as well as the place where the digested particles are absorbed into the
bloodstream. Remember, it would do no good to even eat if the particles could not be absorbed
into the blood and circulated to all of the cells. The small intestine is broken up into three regions,
the duodenum, the jejunum, and the ileum. It is hard to tell where one of these regions ends and
the next begins without the use of microscopes. In function however, most of the chemical
digestion occurs in the duodenum, while most of the absorption of particles occurs in the jejunum
and ileum. The small intestine is long, allowing for the food to spend more time in this organ so
that it has enough time to be digested and absorbed. The small intestine has also increased its
surface area to allow for the maximum amount of digestion and absorption. The small intestine
has folds to increase the area, as well as fingerlike entensions called villi. These villi also have
microscopic fingerlike structures coming off of them called microvilli.
The next organ of the alimentary canal is the large intestine, or colon. The large intestine
is not longer than the small intestine, nor does it have a larger surface area. It is called the large
intestine because the diameter of the intestine is larger. In the fetal pig the large intestine is tightly
coiled and held together by a thin connective tissue called mesentery. This arrangement of the
colon is different than that of the human. The function of the colon is to reabsorb water that has
been added to the food along the way. Land animals must have adaptations to conserve water in
order to survive, and this is just one of many different ways in which we conserve water. In some
cases, bacteria that live inside the colon make vitamins that the animal also absorbs with the
water.
The final part of the large intestine that is not held together with the rest is the rectum. The
rectum stores the feces until it can be eliminated from the body. Storage of the feces is important,
for if animals were constantly defecating, they would leave a trail of feces from which predators
could track them, for instance. The rectum will pass the undigested material from the anal
opening, which is also controlled by a sphincter muscle.
Going back to the place where the small intestine joined the large intestine, there is a small
projection coming from the juncture. This is the cecum. This projection is usually much larger in
herbivores (plant eaters) than carnivores (meat-eaters). The cecum is thought to be an extra area
for digestion, which would be more necessary for herbivores since plants are harder to digest. In
humans, this cecum has a fingerlike projection coming from it called the appendix. This appendix
serves no function in us. An organ that no longer serves a function in an organism, but likely
served a function in the distant ancestors that gave rise to the species is called a vestigial organ.
The appendix and tailbone (coccyx) are two examples of vestigial organs in humans.
Introduction to the Accessory Organs:
The accessory organs of the digestive system do not have food pass through them, but they
are very important to the process of digestion. Often these organs are glands that secrete enzymes
or other digestive juices through a tube or duct to one of the organs of the alimentary canal.
The first accessory organs are three pairs of salivary glands. These glands are located in
the tissue of the face and neck and release saliva into the mouth to mix with the food. The saliva
contains proteins that make it slippery to help lubricate the food as it passes down the esophagus.
The saliva also contains an enzyme that begins the chemical digestion of starch. We will be
unable to see these glands in our dissection.
We will however, see the next accessory organ, the liver. is a large brown organ that fills a
good portion of the abdominal cavity. It has several lobes. The liver has many vital functions
such as detoxifying drugs and poisons, making and storing glycogen, making cholesterol, etc. Its
main digestive function is to produce bile. Bile is not an enzyme. It is a greenish-brown fluid that
contains many salts, pigments, and cholesterol, and its function is to emulsify fats. In other
words, it breaks fats and oils into smaller droplets, increasing the surface area so they will be able
to be digested and absorbed more easily. Underneath one of the lobes of the liver, is a small, thin
walled sac that may appear flattened in your pig. This is the gall bladder, and its function is to
store the bile that the liver is constantly producing, and to concentrate it by removing some of the
water. The bile will pass from the gall bladder to the duodenum of the small intestine through a
small tube or duct called the common bile duct. The gall bladder will be stimulated to release the
bile through the bile duct into the small intestine when food enters the small intestine. If the
common bile duct becomes plugged by mucus or a gallstone (solidified cholesterol and salts), then
the bile cannot reach the small intestine. Instead the bile will enter the blood and cause jaundice.
The main symptom of jaundice is a yellowing of the eyes and skin. This yellowing resulting from
the pigments in the bile.
The final accessory organ is one of the most important of the digestive glands, the
pancreas. The pancreas has many lobes and is a light tan color. It lies under the stomach,
between the stomach and the intestines. The lobes are wrapped by a thin transparent mesentery.
The pancreas releases many important enzymes that perform chemical digestion. These enzymes
are released into the duodenum of the small intestine.
The pancreas not only belongs to the digestive system, but also to the endocrine system.
The pancreas contains special groups of cells that release the hormones insulin and glucagon into
the bloodstream. These groups of cells are called islets of Langerhans. Insulin and glucagon are
important hormones that control the level of glucose in the blood. Individuals that suffer from
diabetes mellitus lack insulin, causing the levels of sugar to rise in the blood. Some of this sugar is
released into the urine.
The pancreas is also an example of an endocrine gland and an exocrine gland. Endocrine
glands release hormones into the bloodstream directly. They do not use a tube or duct to deliver
their contents. Since the islets of Langerhans release their hormones, insulin and glucagon,
directly into the blood, the pancreas is an endocrine gland. But part of the pancreas makes
digestive enzymes that are delivered to the small intestine through a duct. In this respect, the
pancreas is also an exocrine gland.
While the spleen is not a member of the digestive system, we will discuss it at this time,
because it is most noticeable when examining the abdominal organs. The spleen is a reddish
brown strip of tissue that is attached near the stomach and lies along the body wall. It is held into
place by the mesentery. One of the function of the spleen in humans is to destroy blood cells. The
liver and the spleen together destroy about 2 million red blood cells per second in the adult
human. It has been hypothesized that only old, worn-out blood cells are destroyed, but this has
not been proven. Certainly, some of the components of the red blood cells can be recycled by the
body. The spleen also stores red blood cells and can release them into the blood vessels when
needed. For instance, when a person is scared, adrenalin released into the blood causes the spleen
to release extra red blood cells into the blood. This allows the blood to carry more oxygen,
supplying the muscles and cells with more oxygen needed to break glucose down into useable
energy. In addition to storing red blood cells, the spleen also stores white blood cells used to fight
infections in the body. In the embryo, the spleen is the site of red blood cell production, but no
longer performs this function in the adult. In adults, the spleen does not seem to be vital for life.
Procedure:
1. Pin the muscular flaps of tissue away from the abdomen so you can see the internal organs.
Internal organs are called viscera. These viscera are found within the body cavity or coelem
(pronounced see-lum). A smooth transparent membrane called the peritoneum lines the
abdominal cavity and covers the organs. Most of the organs are held suspended by the
peritoneum. Connective tissue like the peritoneum keeps the viscera in their proper place so that
the organs do not all mix around as the organism moves. Blood vessels and nerves also travel
through the connective tissue, or mesentery, in order to connect with the organs.
2. Find the liver. It is the large, most obvious organ in the abdomen.
3. Look underneath the lobes of the liver and find the gall bladder.
4. Find the small common bile duct that connects the gall bladder to the small intestine.
5. Locate the stomach, a large light organ that receives the food. It is under the lobes of the liver
and is toward your right as you view the pig.
6. If you try to find the esophagus that leads to the stomach you will be unable to do it. The
reason for this is that the esophagus lies in the chest cavity, more properly called the thoracic
cavity. The thoracic cavity and the abdominal cavity are separated by a thin muscular sheet called
the diaphragm. Locate the diaphragm that is anterior to the liver and stomach.
7. Locate the pancreas. It is a light colored, many lobed organ that lies under the stomach. It
almost looks like a thin layer of tan-colored cottage cheese between a sheet of Saran wrap.
8. Find the spleen. It is easily seen as a reddish strip of tissue next to the stomach.
9. Locate the small intestine where it connects the stomach. Note that the small intestine, while it
appears to be a jumbled mass, is actually held by mesentery. Look at the mesentery that holds the
small intestine. Can you see red blood vessels running in the mesentery toward the small
intestine?
10. Find the large intestine. This is a tightly coiled mass of intestine wrapped in mesentery.
11. Where the small and large intestine meet, there is a small fingerlike projection called the
cecum. Find the cecum.
12. Cut open the stomach with your scissors. Wash out the stomach under a stream of water in
the nearest sink. The greenish debris that you see are sloughed off epithelial cells that have been
stained by bile. Remember, since the fetal pig has not been born, it has not eaten anything yet.
13. Examine the stomach lining .
14. Look inside of the stomach locate the pyloric sphincter. You should be able to locate this
donut-shaped muscle.
Examining the Fetal Pig
Part Three: The Circulatory System
Purpose:
To study a mammal having anatomy of a human.
To compare the features of mammals to the other phyla that we dissected.
To examine the circulatory system of the Pig.
Materials per Lab Station:
1 fetal pig
1 gallon-sized Ziploc bag
1 dissecting tray
razor blade
probes
scissors
forceps
Gloves
Introduction:
The part of the circulatory system that we will be examining is in the thoracic cavity (chest
cavity) . The thoracic cavity is separated from the abdominal cavity by a thin sheet of smooth
muscle called the diaphragm. The diaphragm contracts and relaxes to allow breathing to take
place. The thoracic cavity is separated into three sections. Two of these sections are the right and
left pleural cavities, each of which contains a lung. Between them is the pericardial cavity,
containing the heart. These sections are not separated by muscle but instead by a thin transparent
mesentery tissue.
When looking at the heart, you should notice the thymus gland. This gland lies over the
heart and is part of the immune system, not the circulatory system. It is thought to be important
in the maturing of T-cells, an important part of the immune response. T-cells are given their name
because they mature in the thymus gland.
The heart itself is enclosed within a transparent membrane called the pericardial sac. Upon
closer examination of the mammalian heart we see that it has four chambers. In a way, the fourchambered heart is like two hearts in one, because it really functions as two pumping units
beating in unison. The heart has two pumping chambers or ventricles which are the lower
chambers of the heart. The upper chambers are the thin-walled atria which collect blood before
sending onto the ventricles. In the adult, blood does not mix from the right to the left sides of the
heart due to the thick septum which separates the right and left ventricles. The heart of a pig also
has auricles which are flap-like structures that sit atop the atria. They also hold blood and serve to
increase the volume of blood that the heart can hold.
When the muscle of the ventricles contract during a heartbeat, blood is squeezed out of the
heart through thick walled, elastic blood vessels called arteries. While we will not dissect your
pig in a way that you will see all of these vessels, there are some vessels worth noting. When you
look at the heart you will see a number of different blood vessels on the heart muscle itself. While
blood fills the heart all of the time, the nutrients that are delivered to the cardiac muscle cells are
actually delivered through arteries that are noticeable on the outside of the heart, which are the
coronary arteries.
The right side of the heart performs pulmonary circulation, meaning it pumps oxygen
poor blood to the lungs. The heart receives oxygen-poor blood into the right atrium from the
largest vein I the body the vena cava. Actually the vena cava is two veins : the superior vena
cava which collects blood from the upper body and the inferior vena cava which collects blood
from the lower body including the kidneys and hepatic vein from the liver. Together these veins
join at the right atrium where they dump blood into it. The blood will then travel to the right
ventricle where it is pumped to the lungs through the pulmonary artery. One pulmonary artery
carries blood to each lung, where the blood will release carbon dioxide and pick up oxygen. The
now oxygen rich blood will return to the heart through the pulmonary veins. These pulmonary
veins empty their blood into the left atrium and then passes into the left ventricle. The left
ventricle will contract under very high pressure and send the blood through the largest artery in
the body, the aorta. The aorta will branch off into smaller arteries to deliver blood to all the
tissues of the body, called systemic circulation.
When the ventricles of the heart, the blood is kept flowing in the right direction due to
valves between the chambers. For instance , between the right atrium and right ventricle are three
flaps that make up the tricuspid valve. Between the left atrium and left ventricle is the bicuspid
valve or mitral valve.
In this introduction we discussed the path in the adult mammal which can be broken into
pulmonary and systemic circulation. In the fetus, blood travels down the same path, but we see
that there are two detours that the blood makes. The reason for this is that the fetus does not
breathe instead it will receive oxygen from its mother. The lungs are partially collapsed and will
not need all of the blood pumped to them that the right side of the heart is capable of sending
them. The fetus has two adaptations that will cut the amount of blood going to the lungs. The
first adaptation is the foramen ovale which is an opening between the right and left atrium. This
will allow some of the blood that enters the right side of the heart to go directly to the left atrium.
The second adaptation prevents blood from reaching the lungs. Normally in an adult, the
pulmonary arteries carries blood to the lungs but in the fetus the ductus arteriosis directly
connects the pulmonary artery to the aorta. This allows the blood to directly bypass the lungs and
be pumped to the body instead.
While these adaptations are great for the fetus, they could be real problems when the fetus
is born and needs to start breathing. At the moment of birth, the fetus will take its first breath,
expanding its collapsed lungs for the first time. At this time, the pulmonary arteries dilate and the
ductus arteriosis closes off and the foramen ovule closes off in the heart.
Procedure:
1. Using your scissors cut a line from the abdomen all the way up to the chin of the pig.
When cutting, you will have to cut through the sheet-like diaphragm that separates the
abdominal cavity from the thoracic (chest) cavity. When making the cut, you must cut
through the sternum and ribs. See diagram below.
2. Notice the three sections of the thoracic cavity. The two pleural cavities with a lung in
each, and the pericardial cavity in the center containing the heart.
3. At the very top of the heart, find the thymus gland. It is relatively light and tan color.
Push the thymus to the side.
4. With the forceps, carefully peel off the transparent membrane (pericardial sac)surrounding
the heart.
5. Locate the right and left atrium and the dark, flap-like auricles that are at the top of the
atria. These chambers help the atria store blood before delivering it to the ventricles.
6. Locate the right and left ventricles of the heart.
7. Locate the coronary arteries on the outside of the heart itself.
8. Locate the superior and inferior vena cava on the left side of the heart
9. Locate the pulmonary artery which is the large, white that easily seen looking at the top of
the heart.
10. Move the heart forward and look at the base of the left lung. You might be able to see the
pulmonary veins that bring blood back to the left atrium.
11. Find the aorta somewhat below the pulmonary artery and to the right of the superior vena
cava. It has several arteries that branch off of it including the carotid arteries that carry
blood to the head.
12. Trace the path of the aorta as it goes down the body cavity. You can do this by moving the
left lung and following the aorta along the dorsal thoracic wall .
13. To see the valves of the heart, make a diagonal cut through the ventral wall of the heart
and extend it to the pulmonary artery. The three flaps are the tricuspid valve.
Fetal Pig Dissection
Period________
Group members:
______________________________________________________________________________
Part 1
Pre-lab questions:
1.
What is a fetus?
2. How many tubes are in the umbilical cord and what do they carry?
3. What are the four mammals mentioned in this lab?
4. Where are the hard and soft palate located? What is the difference?
Observations:
-Length of your pig ______________
Analysis Question: Make sure you answer in complete sentences and make sure your
answer indicates what question was being asked.
1.
What are two mammalian characteristics that you found on your pig?
2. What is the sex of your pig and how did you figure it out?
3.
How many days old is your pig? How did you determine this?
4.
Label the part on the diagrams of the pigs below and determine their sex.
Part 2
Prelab Questions:
You should read through the procedure section before completing
these questions, because some of the answers may come from that section.
1. Digested food is not used just for energy. What else are the particles used for?
2. How are accessory organs different from those of the alimentary canal?
3. List the organs of the alimentary canal in the order that food passes through them.
4. What is the difference between an endocrine gland and an exocrine gland?
5. Where specifically will you find the pancreas in your pig?
ANALYSIS QUESTIONS:
Make sure you answer in complete sentences and make sure your answer indicates what
question was being asked.
1. Describe the appearance of the stomach lining.
2. Describe the appearance of the lining of the small intestine.
3. How does the length of the small intestine compare to the length of the large intestine? Explain
why.
4. What is the main digestive function of the liver?
5. What is the function of the gall bladder?
6. What is the function of the cardiac and pyloric sphincters?
7. What is the function of the esophagus?
8. To what two systems does the pancreas belong?
9. What is the function of the cecum?
Part 3: Circulatory System
Pre-lab Questions
1. What is the ductus arteriosis?
2. Is the blood that enters the right atrium oxygen-rich or oxygen-poor?
3. Blood that enters the inferior vena cava comes from what part(s) of the pig?
4. What would you find in the pleural cavities?
5. What artery is most obvious when you first look at the heart?
Analysis Questions:
1. What is the function of the diaphragm?
2. What is the name of the membrane that surrounds the heart?
3. Explain how the structure of the ventricles relates to their function.
4. What is the function of the coronary arteries?
5. Explain why the blood would bypass the lungs in a fetus.
6. What is the complete path that blood takes in an adult?