Fetal Pig Dissection IntNB

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                 Fetal Pig Dissection

At the end of this unit, I will:

    explain the structure and function of organs
     and organ systems and how they work
     cooperatively within an organism.
    be able to carefully dissect, reveal, and
     identify anatomical features of a fetal pig.

Roots, Prefixes and Suffixes I will be able to understand when I see them in words

    cardio-, veno-, arterio- lymph-, ova-, spermato-, reno-, caudo-, cephalo-,
     hemo-, lympho-, spleno-, thymo-, laryngo-, naso-, pharyngo-, tracheo-,
     esophago-, colo-, pancreato-, gastro-, nephro-, urethro-, sebo-, gonado-,

The terms I can clearly define are:

    Group 1: cell, tissue, organ, organ system, organism
    Group 2: cardiovascular system, muscular system, lymphatic system, immune
     system, respiratory system, digestive system, excretory system, nervous
     system, integumentary system, endocrine system, reproductive system,
     skeletal system.
    Group 3: caudal, cranial, dorsal, ventral, anterior, posterior, distal, proximal,
     medial, lateral
    Group 4: hard palate, soft palate, sensory papillae, esophagus, epiglottis,
     diaphragm, liver, gall bladder, bile duct, duodenum, stomach, small intestine,
     large intestine, mesentery, ileum, pancreas, spleen, cecum, kidney, urinary
     bladder, umbilical vessels, sternum, heart, pericardium, atria, ventricles,
     coronary artery, pulmonary artery, aorta, anterior and posterior vena cava,
     thymus, diaphragm, lungs, bronchial tubes, trachea, renal artery, renal vein,
     ureter, urethra, testis, scrotum, epididymis, vas deferens, penis, ovary,
     fallopian tube, uterine horn, uterus, urogenital sinus, genital papilla

The assignments I will have completed by the end of this unit are:

      Dissection Cover Page
      Fetal Pig Virtual Dissection
      Fetal Pig Dissection
      Fetal Pig Dissection Practical

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Fetal Pig Dissection Student Design Cover Page
          (see guidelines on page 16)

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                                  On-line Virtual Dissection

To prepare ourselves for the task of dissection, we will explore a virtual dissection
online. It is your task to complete the following quizzes prior to dissection in class.
Due dates will be assigned by your individual classroom teacher. To complete the
virtual dissection, go to the following web-page to complete the quizzes on pages
291 – 298 of your interactive notebook:


During this dissection, we will be exploring the following systems in detail.

                              • Digestive System – Day One
                             • Respiratory System – Day Two
                             • Circulatory System – Day Two
                             • Excretory System – Day Three
                           • Reproductive System – Day Three

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                            Anatomical References Quiz

      Label the regions: Pelvic region, Cranial region, Caudal region, Pectoral

      Label the regions: Ventral, Posterior, Dorsal, Anterior

                                     Point of Reference



Circle the correct choice

1. On the pig above, letter A is (medial, lateral). Letter B is (medial, lateral)
2. With respect to marker A, marker B is (proximal, distal) to the point of reference.
3. With respect to marker B, marker A is (proximal, distal) to the point of reference.

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                               Sexing Your Pig Quiz

1. An easy way to determine the sex of your pig is to check for the presence or
absence of nipples. True or False?

2. Only the male pig has a urogenital opening. True or False?

3. The male fetal pig has a developing scrotal sac, a penis, and a urogenital papilla.
True or False?

4. The pig featured below is what sex?

5. Label the diagram using the following terms. Urogenital papilla, umbilical cord,
teats (nipples), anus

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                                Respiratory System Quiz

Fill in the blank using the following terms: lungs, bronchi, diaphragm, nares, trachea.
Following each definition, what number (1-5) did you used to label each of the
structures on your on-line virtual quiz?

________________________ Connects upper and lower respiratory system (number ___)
________________________ Distributes air into both lungs (number ___)
________________________ Contraction creates negative pressure (number ___)
________________________ Air enters the respiratory system (number ___)
________________________ Aids gas exchange with its large surface area
                         (number ___)

Trace the path of gas molecules throughout the body. For this activity, use red
arrows to trace the path of Oxygen (O2) and blue arrows to trace the path of carbon
dioxide (CO2). Draw these arrows using red or blue ink. The first one is done for you
as an example.

                                   Mouth or Nose
   This would be a red arrow.

                    Arteries            Tissues               Veins

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                               Circulatory System Quiz

Determine the proper cycle of blood throughout the body by filling in the flowchart
with the terms: body, right atrium, lungs, left ventricle, right ventricle, left atrium, CO 2
and O2 exchange

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                                 Digestive System Quiz

Identify the organs and their functions by filling in the following descriptions with the
appropriate terms: mesentery, pharynx, gall, nares, pyloric, spleen, rectum, rugae,
large, papillae, salivary, small, pancreas.

1. These ridges in the stomach allow the stomach to expand and hold more food for
digestion. ____________________

2. The ____________________ gland secretes some of the first enzymes in the digestion

3. Located on the tongue of the pig, the sensory ____________________ are responsible
for the sense of taste.

4. The ____________________ sphincter controls the movement of food from the stomach
to the small intestine.

5. This structure appears purplish due to the close proximity of the veins and arteries
running through it.

6. It is the ____________________ bladder that stores and concentrates bile for release in
the stomach.

7. The ____________________ intestine helps finish the digestive process by reabsorbing
water and creating fecal matter.

8. The ____________________ intestine is the main structure responsible for the absorption
of essential nutrients into the body.

9. This structure stores fecal matter prior to excretion.

10. This small structure takes in red blood cells and other cells and breaks them down to
recycle back to the body. ____________________

11. The paired ____________________ are holes in the snout of the pig that facilitate
breathing while warming in-coming air.

12. This organ manufactures digestive juices and enzymes to help portions of the
digestive process. ____________________

Identify the organs 1-6 from the digestive system quiz.

Organ #1 ____________________             Organ #2 ____________________
Organ #3 ____________________             Organ #4 ____________________
Organ #5 ____________________             Organ #6 ____________________

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                               Excretory System Quiz

Fill in the blank using the following terms: renal artery, ureter, bladder, renal vein,
kidney. Following each definition, what numbers, (1-5), did you used to label each
of the structures on your on-line virtual quiz?

      ______________________________ Takes filtered blood from the kidney back to
                                       the heart. (Number ___)

      ______________________________ Transports urine to the bladder for storage.
                                       (Number ___)

      ______________________________ Transports unfiltered blood from the heart to
                                       the kidney. (Number ___)

      ______________________________ Reabsorbs nutrients, secretes wastes by
                                      filtering blood. (Number ___)

      ______________________________ Takes filtered blood from the kidney back to
                                       the heart. (Number ___)

      ______________________________ Stores urine until it can be excreted out of the
                                       body. (Number ___)

Fill in the blank using the following terms: cortex, ureter, renal pelvis, medulla.
Following each definition, what numbers, (1-4), did you used to label each of the
structures on your on-line virtual quiz?

      ______________________________ Collects filtrate from the kidney (Number ___)

      ______________________________ The outer region of the kidney (Number ___)

      ______________________________ Takes collected waste from the kidney to the
                                       bladder(Number ___)

      ______________________________ Inner portion of the kidney. (Number ___)

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                           Reproductive System Quiz

Label the parts of the female reproductive system based on the image you see on
your virtual quiz.

1. _______________________________

2. _______________________________

3. _______________________________

Label the parts of the male reproductive system based on the image you see on
your virtual quiz.

1. _______________________________

2. _______________________________

3. _______________________________

4. _______________________________

5. _______________________________

Put the structures in order that the unfertilized egg passes through the reproductive

1. _______________________________

2. _______________________________

3. _______________________________

4. _______________________________

5. _______________________________

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                            Reproductive System Quiz

Put the structures in order that the male sperm passes through.

1. _______________________________

2. _______________________________

3. _______________________________

4. _______________________________

5. _______________________________

Match the following terms with the description of its function: cervix, oviducts, testes,
testosterone, urethra, vagina, scrotal sac, ovaries, uterus, epididymus, vas

      __________________________ contain eggs and release hormones

      __________________________ the principal sex hormone in the male is…

      the fetus develops in the __________________________

      __________________________ These tubes carry sperm from the testes to the

      Fertilization normally occurs in the __________________________

      __________________________ contain eggs and release hormones

      __________________________ produce sperm and release sex hormones

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Label the anatomical direction, according to the lecture notes.

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                           Topic: Introduction to Fetal Pig Dissection

Define the following
anatomical regions:

Cranial                          Cranial – head region
Caudal                           Caudal – tail region
Dorsal                           Dorsal – back region
Ventral                          Ventral – stomach region
Anterior                         Anterior – towards the front
Posterior                        Posterior – towards the back

What is the difference
between medial and         _____________________: closer to the trunk.
                           _____________________: further from the trunk.

What is the difference
between proximal and       _____________________: closer to a reference point.
                           _____________________: further from a reference point.

                           For example, the elbow is ______________ to the shoulder, while the
                           wrist is more __________________ to the shoulder.
Consider their
classification and think
about the similarities
between human and

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We study and dissect fetal pigs due to their physiological and anatomical similarities
to humans. Brainstorm ways in which their basic appearance and internal anatomy
may be similar or different.

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                          Topic: Introduction to Fetal Pig Dissection

What lab safety rules
must we follow in
order to protect
ourselves, our
classmates, and to
respect the life of the
fetal pig during the
dissection lab?

To determine the age
of your pig:

To determine the sex
of your pig:

What feature is unique
to females? males?

Decide on ventral-
incision style based
upon the gender of
your fetal pig

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                   Fetal Pig Dissection

External Anatomy


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                                Fetal Pig Dissection

Objective: In this exercise you will examine the organization of the many body
systems studied this semester in the context of a single specimen, the fetal pig. Be
sure to identify the major organs as you explore the extent of each system.

Day 1: External Anatomy and Digestive System

External Anatomy

    Examine the fetal pig and locate the external features shown to the left.

    Two rows of nipples of mammary glands are present on the ventral
     abdominal surface of both males and females. Mammary glands later
     develop only in maturing females.

    Determine the gender of your specimen.
     Female: The urogenital opening in the female is immediately ventral to
     the anus and has a small genital papilla marking its location.
     Male: The scrotal sac is ventral to the anus and a urogenital opening is
     just posterior to the umbilical cord.

      What is the gender of your pig? ____________________

    Gestation for the fetal pig is 112 – 115 days. The length of the fetal pig can
     give you a rough estimate of its age.

                                    11 mm – 21 days
                                    17 mm – 35 days
                                    2.8 cm – 49 days
                                     4 cm – 56 days
                                    22 cm - 100 days
                                30 cm or greater – full term

      How old is your pig? ____________________

    Observe the toes of the pig. How many toes are on the feet? ________

      Do they have an odd or even number of toes? __________

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Oral Cavity

First Incisions



                  3.   3.

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Oral Cavity

    To expose the structures of the mouth and pharynx, start by inserting a pair of
     scissors in the angle of the lips on one side of the head and cut posteriorly
     through the cheek. Open the mouth as you make your cut and follow the
     curvature of the tongue to avoid cutting the roof of the mouth.

    Now, repeat the procedure on the other side so that the lower jaw can be
     pulled down to expose the structures of the mouth and pharynx as shown in
     the image to your left.

    Locate the hard and soft palate on the roof of the mouth. Feel your own hard
     and soft palate with your tongue.

    Note the taste buds (sensory papillae) on the side of the tongue.

    Locate the esophagus at the back of the mouth. The esophagus eventually
     leads to what large J-shaped digestive organ? ________________________

    Feel the edge of the mouth for teeth. Does the fetal pig have teeth? ______

      Are humans born with teeth? _______

    Locate the epiglottis, a cone-shaped structure at the back of the mouth. This
     is a flap that helps to close the larynx that leads down to the lungs when the
     pig swallows, preventing food from entering the respiratory pathway.

Preparing for the first incisions

                          Use the scalpel only when absolutely necessary.
                    You will mainly be working with blunt probes and scissors.
Lift up as you cut, putting the blunt area of the scissors facing down and the sharp end facing up.
                                     Always cut away from you.

    Place the pig on its dorsal surface in the dissecting tray. Tie a piece of string or
     twine around the wrist of one forelimb. Then, pass the string under the tray
     and tie it to the other wrist. Tie and spread apart the pig’s hind legs as you did
     with the forelimbs.

    Use dissecting scissors to cut through the skin and muscles along lines 1 – 4 to
     open up the abdominal cavity. (do not make incision 5 to open up the
     thoracic or chest cavity) Transverse incision #4 is made just below the rib
     cage. The flap formed by incision 2 will remain attached to the main part of
     the pig’s body. To free this flap of tissue, cut the vein leading into the umbilical

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Body Cavity


                  Umbilical vessels

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Locate each of the following organs below. Check the box when you have located
the structure. Do not cut out any structure, unless instructed to do so.

 Diaphragm. This muscle divides the thoracic (chest) and abdominal cavity. It is
  located near the ribcage. The diaphragm aids in breathing.
 Liver. This structure is lobed and is the largest organ in the body. The liver is
  responsible for making bile for digestion.
 Gall bladder. Lift the liver to see this structure. This greenish organ is located
  underneath the liver. It may look like a raisin. The bile duct attaches the gall
  bladder to the duodenum, or the first section of the small intestines where the
  absorption of nutrients begins, particularly bile helps to digest lipids. The gall
  bladder stores bile and sends it to the duodenum, via the bile duct.
 Stomach. A “J” shaped organ that rest just beneath the liver to the pig’s left. At
  the top of the stomach, you will find the esophagus. The stomach is responsible
  for churning and breaking down food. This is where the mechanical digestion
  takes place. Food is also stored in the stomach, and released a little at a time
  into the small intestine.
 Small intestine. The stomach leads down 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. In the small intestine,
  further digestion occurs and nutrients are absorbed through the arteries in the
 Pancreas. A bumpy organ 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 is part of both the
  digestive and endocrine systems.
 Spleen. A flattened, long organ that lies slightly under the stomach and toward
  the extreme left side of the pig. The spleen removes old red blood cells.
 Cecum. At the end of the ileum, where it widens to become the large intestines,
  a dead-end branch called the cecum is visible. The cecum helps the pig digest
  plant material.
 Large intestine. This organ follows the small intestines and 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 anus. The large intestine reabsorbs
  water from digested food. Any undigested food is stored in the rectum as feces.
 Kidneys. 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.
 Urinary bladder. Two umbilical vessels can be seen in the umbilical cord, and
  the flattened urinary bladder lies between them.

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Thoracic Cavity

Fetal Pig Heart, Ventral View

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Day 2: Circulatory and Respiratory Systems

It is important that you do not break the vessels since it is very difficult to determine
the name of the vessels unless you can see where it comes from and where it goes.
The blood vessels have been stained in your pigs. Red blood vessels carry
oxygenated blood (typically arteries) and blue blood vessels carry deoxygenated
blood (typically veins).

    Open the chest cavity, by making incision #5 with dissecting scissors, as
     marked on page 305 of your interactive notebook. To open the thoracic
     cavity, you will have to cut through the sternum that connects the ribs.
    Heart. Remove the pericardium, which is a membrane that surrounds the
     heart to view the heart. The heart pumps blood throughout the body,
     circulating oxygen, carbon dioxide, nutrients, hormones, and other dissolved
    The structures visible on the heart are the two atria (upper heart chambers)
     and the ventricles (lower heart chambers). The two ventricles are divided by
     the coronary artery that runs down the middle of the heart.
    The prominent pulmonary artery can be seen leaving the pig’s right ventricle.
     This artery goes to the lungs. A large aorta (vessel) arches and leaves the
     heart and delivers blood throughout the body. The aorta will branch toward
     the head and curves around to go to the lower part of the body.
    Lift the heart to look at its dorsal side (toward the back). You should be able
     to see the anterior and posterior vena cavae, stained blue. The anterior vena
     cava returns blood to the heart from the head, while the posterior vena cava
     returns the blood to the heart from the lower half of the body.
    Above the heart is the thymus gland. This gland extends into the neck on
     each side of the trachea. The thymus is part of the immune system, where T-
     cells mature.
    Find the diaphragm again. Remember that the diaphragm separates the
     abdominal cavity from the thoracic cavity and it aids in breathing.
    The lungs are spongy and are found to the left and right side of the heart. The
     lungs are connected to bronchial tubes which connect to the trachea.
    The trachea is easy to identify due to the cartilaginous rings, giving it the
     appearance of a bendy straw. The cartilage keeps it from collapsing as the
     animal inhales and exhales.

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Male Reproductive and Excretory Systems

Day 3: Reproductive and Excretory Systems

You will dissect your own pig, but make sure to view both male and female pigs by
examining other groups’ dissections.

    Locate the kidneys. The blue veins leading out of the kidneys are the renal
     veins, returning blood to the heart. The red arteries leading towards the
     kidneys are the renal arteries, delivering blood from the heart.
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   The tubes that lead from the kidneys that carry urine are the ureters.
   The ureters carry urine to the urinary bladder where urine is stored until it is
    ready to be excreted. The urinary bladder is found in between the umbilical
   Follow the urinary bladder and you will find the urethra, the tube that carries
    urine out of the body.

Male Reproductive System

   Find the scrotal sacs at the posterior end of the pig. The testis is located in
    each sac. Open the scrotal sac to locate the testis, being careful not to
    damage the testis.
   On each testis, find the coiled epididymis. Sperm cells produced in the testis
    pass through this tube, where they mature. After maturation, they enter a
    tube called the vas deferens. (in humans, a vasectomy involves the cutting of
    this tube.)
   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 Excretory and Reproductive System

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Fallopian tube

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Female Reproductive System

    In the female pig, locate the two bean shaped ovaries found just posterior to
     the kidneys.
    The ovaries are connected to the fallopian tubes, which carry eggs from the
     ovaries to the uterine horns. (The uterus of the pig is different from that of the
     human, as it is divided into two horns before joining together as one uterus.
     Remember pigs give birth to litters.)
    The uterus can be traced posteriorly to the vagina, which simply appears as a
     continuation of the uterus.
    The common area between the vagina and the urethra is called the
     urogenital sinus.

Finishing Up

    Time permitting, feel free to revisit any part of this exercise.
    Make sure that you can identify all terms that are in bold, as you will be
     responsible for identifying these parts on your lab practical.
    Identify both male and female structures.
    Dispose of your specimen, according to your teacher’s instructions.
    Disinfect and sanitize your lab space, wash your hands, and clean up.

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Dissection Unit Concept Map

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                           Parent/ Significant Adult Review Page

                                       Student Portion
Unit Summary (write a summary of the past unit using 5-7 sentences):

Explain your favorite part of the dissection:

                                             Adult Portion
Dear Parent/ Significant Adult:
This Interactive Notebook represents your student’s learning to date and should contain the work
your student has completed. Please take some time to look at the unit your student just completed,
read his/ her reflection and respond to the following

Ask your child to explain to you the pig dissection process. What three facts did you learn from your

Do you think your child benefited from this dissection? Please explain.

Parent/ Significant Adult Signature:

Comments? Questions? Concerns? Feel free to email your child’s teacher.

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