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7/24/2019 Examining the Fetal Piggsdfgsdfgsdfg

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Examining the Fetal Pig

Part One: External Anatomy and Beginning the Dissection

Purpose: 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.

Materials: 1 fetal pig probes

1 gallon-sized Ziploc bag scissors

1 dissecting tray scalpel or razor blade

forceps 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 mothers 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 wasnot 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


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260 mm pig is about 110 day 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 thescrotal sacscontaining thetestes. 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. Theurogenital 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. Thepenislies 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 smallurogenital 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 thegenital papilla. The male

does not have agenital 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 mothers uterus and at theplacenta,materials from the mothers blood and fetuses blood are exchanged. Nutrients that the fetus need

will diffuse from the blood vessels in the mothers uterus into the fetal blood found in the

placenta. Likewise, waste from the fetuses blood will enter the mothers 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 theumbilical cord. Part of theumbilical cordstill remains on the fetal pig that

you are dissecting. In a cross section of the umbilical cord, two thick walledumbilical arteries

can be seen. The arteries carry blood from the fetus to the placenta, where they exchange waste

for nutrients with the mothers blood. Also in the umbilical cord is a larger thin walled vessel that

may be flattened called theumbilical vein. The vein carries blood back from the placenta to thefetus. Finally there is theallantoic ductwhich 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 theumbilical cordand 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 thehard palate,

which is the bony, upper roof of the mouth cavity. It has a ridged appearance. Thesoft

palateis a continuation of the hard palate that extends toward the back of the throat(it does

not have bone beneath it).

5.Locate thelipsandexternal nares(nostrils).

6.Locate theexternal ears.


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Beginning the Dissection:

1. Throughout the dissection it is important thatyou 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 theumbilical cordto remove this ventral flap back toward the leg, but

you may have to cut theumbilical veinthat extends to theliverto 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.


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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 probes

1 gallon-sized Ziploc bag scissors1 dissecting tray forceps

gloves 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. Thealimentary canalis 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 themouth, and the

opening through which the undigested materials leave the alimentary canal is theanus. 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


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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 theaccessory 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 themouth cavity. It is in this chamber that digestion

begins. Theteeth,tongue, andhard palateall work together to begin breaking the food downmechanically. In other words, physical force is used to break down the food. This type of

digestion is calledmechanical 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 theepiglottiscovers the opening of the windpipe during swallowing to

prevent food or liquid from entering the lungs by accident. The esophagus is a muscular tubethat will pass food to the stomach. The food travels through the esophagus and the rest of the

alimentary canal by peristalsis.Peristalsisis the rhythmic contractions of smooth muscles in the

walls of the esophagus (and the organs following the esophagus) that push the food along.

Thestomachis 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, thesmall

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 digestionis the use of enzymes and other chemicals

to break food into smaller particles. It is chemical digestion that breaks the food into particlessmall enough to be absorbed. Where the esophagus joins the stomach is thecardiac sphincter. A

sphincteris 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, thepyloric 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


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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 thesmall 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 thelarge intestine, orcolon. 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 therectum. 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 theanal

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 thececum. 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. Inhumans, this cecum has a fingerlike projection coming from it called theappendix. 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:


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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 ofsalivary 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, theliver. 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 producebile. 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 thegall 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 thecommon 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 hormonesinsulinandglucagoninto

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

glandsrelease 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 anexocrine gland.


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While thespleenis 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 theliver. It is the large, most obvious organ in the abdomen.

3. Look underneath the lobes of the liver and find thegall bladder.4. Find the small common bile duct that connects the gall bladder tothe 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 theesophagusthat 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

thediaphragm. Locate the diaphragm that is anterior to the liver and stomach.

7. Locate thepancreas. It is a light colored, many lobed organ that lies under thestomach. 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 bymesentery. 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 thelarge intestine. This is a tightly coiled mass of intestine wrapped in mesentery.


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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 PigPart 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.


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Materials per Lab Station: 1 fetal pig probes

1 gallon-sized Ziploc bag scissors

1 dissecting tray forceps

razor blade Gloves

Introduction:

The part of the circulatory system that we will be examining is in thethoracic cavity(chest

cavity) . The thoracic cavity is separated from the abdominal cavity by a thin sheet of smooth

muscle called thediaphragm. 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

leftpleural cavities, each of which contains a lung. Between them is thepericardial 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 thethymus 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 thepericardial sac.

Upon closer examination of the mammalian heart we see that it has four chambers. In a way, the

four-chambered heart is like two hearts in one, because it really functions as two pumping units

beating in unison. The heart has two pumping chambers orventricleswhich are the lower

chambers of the heart. The upper chambers are the thin-walledatriawhich 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 thickseptumwhich 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 theheart through thick walled, elastic blood vessels calledarteries. 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 thecardiac musclecells 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 performspulmonary 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 thevena cava. Actually the vena cava is two veins : thesuperior vena cavawhich collects blood from the upper body and theinferior vena cavawhich collects blood from

the lower body including the kidneys andhepatic veinfrom 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 thepulmonary 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 thepulmonary veins. These pulmonary veins

empty their blood into the left atrium and then passes into the left ventricle. The left ventricle will


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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,

calledsystemic 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 thetricuspid valve. Between the left atrium and left ventricle is thebicuspid

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 theforamen ovalewhich 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 theductus arteriosisdirectly

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

theductus arteriosiscloses off and theforamen ovulecloses 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-likediaphragmthat separates the

abdominal cavityfrom thethoracic (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 twopleural cavitieswith a lung in

each, and thepericardial cavityin the center containing the heart.

3.At the very top of the heart, find thethymus 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.


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5.Locate the right and left atrium and the dark, flap-likeauriclesthat 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 leftventriclesof the heart.

7.Locate thecoronary arterieson the outside of the heart itself.

8.Locate thesuperior and inferior vena cavaon the left side of the heart

9.Locate thepulmonary arterywhich 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 veinsthat bring blood back to the left atrium.

11.Find theaortasomewhat 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 thetricuspid valve.

Fetal Pig Dissection Period________ Group members:


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______________________________________________________________________________

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 youranswer 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?


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4. Label the part on the diagrams of the pigs below and determine their sex.


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Part 2

Prelab Questions: You should read through the procedure section before completingthese 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.


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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 SystemPre-lab Questions1. 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.


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6.What is the complete path that blood takes in an adult?

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Examining the Fetal Piggsdfgsdfgsdfg