Anatomy:
Anatomy of Pig Digestive and Respiratory Systems
Purpose
The purpose of this investigation is to study the anatomy and physiology of the digestive and respiratory systems
by performing a fetal pig dissection.
Learning Objectives
Perform a fetal pig dissection, examining the digestive and respiratory systems.
Know the major differences between the fetal and adult condition in these organ systems.
Know the names and functions of all structures, organs, and anatomical terms highlighted in bold print
throughout this text.
Materials
Materials
Fetal pig
2′ length of string
Dissecting pins
Dissecting tray
Label
Dissecting kit
Dull probe
Summary
The objectives of this laboratory exercise are to provide you with practical knowledge of anatomy and physiology
of two major organ systems, the digestive and respiratory systems, and how they respond to internal and external stimuli. You will also learn about how each system interacts. You are responsible for knowing all the boldface
vocabulary and for being able to identify all organs, organ tissues, and anatomical terms for all dissections and
demonstrations. You should know both their form (e.g., be able to identify them) and function (e.g., what
they do), in addition to how they are connected to each other both physically and physiologically.
For a good overview on how to do a good fetal pig dissection, see Pig Dissection
Take your time! You should use the full lab period to identify and study each structure and what it does!
Catalyst Education OER Labs are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 license.
To access our full list of experiments visit https://links.labflow.com/OER. Lab Version PADR Release 3.28.
PADR.1
Anatomy of Pig Digestive and Respiratory Systems
Background
The pig is very similar in many respects to the human, so we can learn much about our own anatomy and function by studying the pig. These pigs are a byproduct of the pork industry, and we are using what would otherwise be
thrown away. The size of your pig depends on its stage of development; gestation is about 16 weeks (3.7 months),
and the newborn piglet is about 30–35 cm (12–14′′) long. The two major anatomical differences between humans
and pigs, apart from the obvious difference in general appearance, are 1) the bicornuate uterus in the female
pig, 2) one opening (urogenital opening) for both the urethra and vagina in the female pig and 3) the lack of an
appendix in all pigs.
Digestive System
The digestive system is responsible for absorbing nutrients and water and removing certain (solid) wastes. You
are responsible for knowing the entire system, from mouth to anus, including most associated organs and glands.
Respiratory system
In vertebrates, the respiratory system develops embryonically as an outgrowth of the pharyngeal part of the digestive tract. The respiratory system is responsible for gas exchange, bringing oxygen into the lungs for transport
to the tissues, where carbon dioxide is released as waste into the blood and transported back to the lungs, where
it is exhaled.
General notes and guidelines
1.
You will work in teams of 2–3 students per pig. It works well for one student to read the directions,
observe, and make notes while the other performs the actual dissection. Trade off from time to time, as
you wish.
2.
When you have finished each major section of your pig, have your lab instructor check your pig to
ensure that you’ve completed the dissection correctly and are ready to proceed without damaging other
structures. Ask your instructor if you are unsure of major steps.
3.
We take a strongly functional approach to understanding the anatomy of the pig and its relationship
to the human. Therefore, you are responsible for all the structures and organs listed and for their
functions, which may be given in this manual but can also be found in your textbook.
4.
Even though you are dissecting a male or a female pig, you are responsible for the functional anatomy
of both sexes. Therefore, share observations with a neighboring team. Sex differences are mostly limited
to urogenital anatomy (external and internal).
5.
Another major theme is to compare fetal and adult anatomy and function, including differences in
function or structure. These differences will be most conspicuous in the digestive, respiratory, excretory,
and circulatory systems.
PADR.2
Anatomy of Pig Digestive and Respiratory Systems
6.
These pigs are ‘doubly-injected’, meaning that the blood vessels have been injected with latex: blue in
the veins, red in the arteries. The injection was done into the external jugular vein through an incision
in the side of the neck (which you can see) and into the umbilical artery.
Answer the Background Questions in the Report Sheet before performing your dissection.
Tips on good dissection technique
1.
You may use gloves provided for you. The pigs are preserved in a non-toxic embalming fluid.
2.
Be patient. Good dissection takes time.
3.
If it is available, examine the dissection on exhibit or a dissection completed by your neighbor before
you begin a new section so that you don’t damage structures or organs that you will need to see later.
Ask your lab instructor if you are uncertain about any major steps.
4.
Make only a few major incisions with the scalpel or scissors. Be very careful not to cut so deeply that
you damage deeper-lying structures. Remember that if you cut too shallow, you can always cut deeper,
but you cannot ‘uncut’ something that should not have been cut.
5.
Most dissections are carefully done by teasing or picking away at the surrounding tissues to reveal the
target organ. The best dissecting tools are your fingers, forceps, or the mall (dull) probe.
6.
Do not remove organs from the pig unless instructed to do so. Instead, remove surrounding tissues to
fully reveal the desired organ and see its relation to nearby organs and structures. A mere glimpse of an
organ or structure is not sufficient. Often the function of an organ will be clarified by understanding its
relationship to other nearby organs.
7.
From time to time, as needed, rinse your pig (initially the external surface, and later, the body cavity)
to remove loose tissues, coagulated body fluids, etc. Discolored water and fluids make it difficult to see
structures.
8.
At the end of each laboratory period, clean up your tray and table, discarding tissues and organs in the
specially provided bags and not in the sink. Store your pig, labeled with its name (be creative!) and your
names/initials, in a plastic bag for next lab.
PADR.3
Anatomy of Pig Digestive and Respiratory Systems
Terms of orientation
1.
The terms right and left refer to the PIG, not to YOU. Remember the pig is usually lying on its back as
you view it, so apparent right and left may be reversed.
2.
Understand the following terms: dorsal (toward the back), ventral (toward the belly), anterior (toward the head), and posterior (toward the tail); proximal: near the point of attachment; distal: far
from the point of attachment (usually used in discussing a limb or other projection); medial, toward
the midline, and lateral, toward the sides of the body (usually used in discussing the body proper).
Supplemental materials and observations
1.
There are posters and models that illustrate organ systems in the human. Be sure to observe and understand these. Especially look for differences between the human and other mammals, such as the
pig.
2.
There are preserved organs from other animals, such as the sheep and cow. These often will provide
larger and clearer views of certain organs and structures.
PADR.4
Anatomy of Pig Digestive and Respiratory Systems
Procedure
Part I. External Anatomy
1.
Obtain a pig from your lab instructor and wash it with tap water.
2.
Obtain a dissecting tray, a 2-foot length of string, a label, and dissecting pins. You should have your own
dissecting kit (be sure yours has a dull probe).
3.
Determine the sex of your pig and try to ensure that you have a pig that is of a different sex than that of your
neighbors’ pigs, so that you can share observations of sex-specific structures.
4.
Write your pig’s given name (and your own initials) on the label and tie it around a leg of the pig for identification.
5.
Note the following parts on your pig and, for external sex organs, compare with a neighboring pig of the
opposite sex:
i.
Major body regions: Head, neck, trunk (with thorax and abdomen), tail. All may be covered with
a thin, peeling layer of embryonic skin, which sloughs off as hairs develop beneath it. Our pigs may
already have some fine body hair.
ii.
Head:
• Mouth, lips, upper and lower jaws, tongue, vibrissae (‘whiskers’)
• Snout, external nares (‘nostrils’)
• Eyelids, eyelashes, nictitating membrane (see this easily by probing the medial corner of
the eye beneath the eyelid with a dull probe
• Pinnae or auricles (‘ear flaps’) and the external auditory meatus, which is the passage
leading to the eardrum.
iii.
Abdomen and external sexual characteristics:
• Mammae (‘teats’)
• Anus, located just below the tail
• External sexual characteristics:
–
Male: has the orifice of the penis just behind umbilical cord and a scrotal swelling
ventral to anus (at maturity, the scrotum will contain the testes and will descend
from the body).
–
Female: has the urogenital orifice (the common orifice of the urinary tract and the
vagina) and a small, spike-like genital papilla ventral to anus.
PADR.5
Anatomy of Pig Digestive and Respiratory Systems
iv.
Umbilical cord: Make a fresh cut across the cord approximately 1 cm from the abdomen, and observe the large, thin-walled umbilical vein [blue-injected]; two smaller, but thickerwalled umbilical
arteries [red]; and between or near the arteries, the allantoic duct or stalk.
v.
Appendages: Pigs, and their relatives (cows, deer, sheep) are ungulates, meaning that they have hooves.
They walk on their toes (‘unguligrade’), of which they have four. The two larger toes correspond to
our middle and ring fingers and the small toes correspond to our forefinger and ‘pinky’. The large toe
(‘thumb’ of our hand) has been lost evolutionarily.
Part II. The head, oral cavity, and pharynx
The mouth enters the oral cavity, which is below the hard palate (important for feeding and speech) and above
the tongue. Behind this, and beneath the soft palate (responsible for closing off the nasal passages during the act
of swallowing, and for closing off the airway. During sneezing, it protects the nasal passage by diverting a portion
of the excreted substance to the mouth), is the oral pharynx (area of the throat at the back of the mouth). Above
the soft palate is the nasopharynx (nasal part of the pharynx) is the uppermost part of the pharynx. It extends
from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the
pharynx in that its cavity always remains open). Recall that the pharyngeal (‘gill’) slits open into the pharynx in
primitive chordates and vertebrates. In the embryonic mammal, certain gill pouches form in this region, but as
the embryo develops, they regress or are transformed into other structures (e.g., the Eustachian tubes, thymus
gland, tonsils).
PADR.6
Anatomy of Pig Digestive and Respiratory Systems
Side of the Head—Salivary Glands and Ducts
1.
Carefully remove the skin from one side of the pig’s head, exposing a triangular area from roughly the anterior of the jaws to the base of the ear to the attachment of the foreleg. You must remove the connective
tissue, subcutaneous fat, and some of the subcutaneous muscle, but be careful not to remove or damage the
salivary glands.
2.
Muscle tissue consists of small parallel bundles of fibers, whereas glandular tissue is lobate, containing
small nodules of tissue clustered in bunches. Identify the large, round masseter muscle, which overlies
the angle of the lower jaw and is partially responsible for closing the jaws. Clench your own jaws and feel
your masseter muscle tighten at the back of your lower jaw.
3.
The salivary glands may be difficult to see well in young pigs but look for at least these two:
i.
The parotid gland is the largest salivary gland, and is superficial, roughly triangular mass of glandular
tissue just behind the masseter muscle and below the ear. The parotid duct may be seen coursing anteriorly ventral to the masseter muscle and then dorsally to the upper jaw (distinguish it, though, from
the whiter, tougher, facial nerve, which has branches running below and along the top of the masseter
muscle).
ii.
The mandibular gland lies beneath (medial to) the parotid gland, just posterior to the masseter, and is
a smaller yet more discrete mass of tissue than the parotid. The mandibular duct runs forward beneath
the masseter and other muscles and opens into the mouth beneath the tongue.
4.
In addition to these two, there are the buccal and sublingual glands. The saliva is the combined secretion
of all the salivary glands, and it contains amylase, water, and mucus.
Structures of the oral cavity
The initial processing of food takes place in the oral cavity and pharynx, where teeth (chewing), the tongue
(manipulating food), the hard palate (both chewing and food manipulation), and saliva (lubrication and initial
starch digestion) all play important roles.
1.
Using a scalpel or scissors, carefully cut the angles of the jaw on either side to expose the oral cavity.
2.
Cut 1–2′′ toward the base of the ear and take care not to cut into the tongue or into the roof of the mouth.
Stay between them and cut back far enough to reveal the hindmost part of the tongue, where you will see
the glottis and the esophageal opening.
PADR.7
Anatomy of Pig Digestive and Respiratory Systems
3.
In the roof of the mouth, behind the hard palate, you will see the soft palate and the opening to the nasopharynx. Use large dissecting pins to hold the two jaws open during your examination.
4.
Hold the two jaws open, and, moving from anterior to posterior, in the oral cavity and pharynx, identify the
following and answer accompanying questions in the Report Sheet:
• Teeth, then in the roof of the mouth see the...
• Hard palate, and behind it the...
• Soft palate and opening to nasopharynx.
• Tongue; see the demonstration slide of the tongue section; find the taste buds, which in many mammals
lie deep in the walls of the papillae; then, toward the rear of the tongue, find the...
• Glottis, which is the opening of the larynx and trachea. This in turn leads to the...
• Epiglottis; and just dorsal to the glottis and epiglottis, the opening to the...
• Esophagus, which leads to the stomach.
Part III. Thorax
1.
Now tie your pig upside down (belly up) securely in the tray by tying strings between the front feet and
between the hind feet, both strings running under the tray.
2.
When making the following cuts, first trace the incision with a shallow scalpel cut through the skin. Then
continue the cut through the rest of the body wall with scissors:
i.
To expose the viscera, make a careful cut (line 1 in Figure PADR.1) from the tip of the chin (there’s a
small papilla with some whiskers) to just anterior to the umbilical cord. Cut through the body wall, but
not deeply enough to damage organs within. Use scissors for this cut and pull the body wall up toward
you so you do not cut into the deeper organs.
ii.
Then continue this incision in a horseshoe shape (line 2) on either side of the umbilical cord and just
outside the teat-line to the posterior base of each hind leg, again being careful not to cut deeper organs.
iii.
Now locate by feel where the rib cage ends and make an incision (line 3) laterally from the midline to
the sides of the pig, being careful to stay below (posterior to) the diaphragm, a broad muscle separating
the thoracic from the abdominal cavities.
iv.
Finally, make a similar lateral incision (line 4) from the branches of the ‘horseshoe’ to just anterior to
each hind leg.
PADR.8
Anatomy of Pig Digestive and Respiratory Systems
Figure PADR.1: Pig dissection
3.
In order to reveal the organs in the abdominal cavity, you will need to pull back the umbilical cord and, associated with it, the bladder, umbilical arteries and, in males, the penis. However, the umbilicus is ‘attached’ to
the internal viscera by the umbilical vein, which courses from the umbilical cord through the body cavity
into the liver. Before you cut the umbilical vein, tie two pieces of thread or string around it, both near
the umbilical cord.
4.
Then cut the umbilical vein between the two strings. This will permit you to pull back the umbilical cord,
but still locate the umbilical vein when you need it in the next lab.
5.
After these incisions are completed and the umbilical vein is tied and cut, separate the cut parts to open the
body cavities and wash your pig thoroughly to remove coagulated body fluid from the abdominal cavity.
6.
You may then use large dissecting pins to pin out the sides of the abdomen.
Resist the temptation to ‘jump’ right into the abdominal cavity, as we will first examine
the organs of the neck, continuing to follow the digestive and respiratory systems from
their beginning.
PADR.9
Anatomy of Pig Digestive and Respiratory Systems
Part IV. The Organs of the Neck
1.
You can reveal this region more clearly if you remove some of the skin overlying the neck organs. Do not
cut too deeply and be careful not to cut major blood vessels (appearing blue or red in your injected pigs).
Remember that muscle usually appears banded and bundled, whereas glandular tissue
appears as if it has nodules or lobes.
2.
Identify the following structures and organs, remembering to associate each with its function. Answer the
accompanying questions on the Report Sheet:
i.
Probably the most conspicuous organ in the neck region in your pigs is the thymus gland, which is
pale, lobulated, and lies in large masses on either side of the midline of the neck. The thymus gland is
conspicuous in the fetus, because it serves early in life to stimulate the production of T lymphocytes, a
kind of white blood cell that is very important in the immune system. Once the immune system is well
established, the thymus gland degenerates, and it is small or nearly absent in the adult. It is the T cells
that become infected with the AIDS virus, or HIV.
ii.
Carefully cut longitudinally through the ventral or dorsal wall of the larynx to reveal the vocal cords,
small whitish folds on its lateral walls.
iii.
At the base of the larynx is the thyroid gland, a dense, reddish-brownish, heart-shaped gland. The
thyroid, another endocrine gland and one that has importance throughout life, secretes thyroxine and
other hormones that control embryonic and later development and regulate metabolism, heat production, and blood calcium levels (which in turn influence bone growth).
iv.
Gently lift the thyroid gland to see the trachea, the tube that leads from the glottis to the bronchi
and lungs. The larynx is the anterior-most part of the trachea. You may need to scrape away a bit of
connective tissue from around the trachea to see that it bears incomplete rings of cartilage. the trachea
must remain open at all times. Contrast this circumstance with the esophagus, below, which is usually
a collapsed tube, except when we swallow food or water.
3.
Examine a prepared slide of a cross section of mammalian trachea. Observe the highly ciliated lining
epithelium and the goblet cells it contains. In some sections you will see partial rings of cartilage, the
function of which was discussed above. Make a drawing of the slide and answer accompanying questions
in the Report Sheet.
4.
Careful probing below the trachea will reveal the esophagus, a flattened tube that leads from the pharynx
to the stomach. Again, you can demonstrate this connection by gently inserting your dull probe into the
PADR.10
Anatomy of Pig Digestive and Respiratory Systems
esophagus at the back of the tongue and see that it continues down the esophagus toward the stomach.
Notice that, in contrast to the trachea, the esophagus is normally collapsed. It is pushed open only by the
passage of food through its lumen.
5.
Examine a prepared slide of mammalian esophagus and note how dramatically it differs from the trachea.
Identify the stratified squamous epithelium that lines it and the deeperlying smooth muscles that are responsible for peristaltic contractions that move food through the esophagus. Make a drawing of the slide in
the Report Sheet.
Part V. Organs of the thorax
Lungs and heart: We will examine the heart in greater detail in the next lab, but here you can identify the major
components of the thoracic region.
1.
The diaphragm separates the thoracic and the abdominal cavities.
2.
The body cavities in which the organs lie comprise the coelom, which is lined with a shiny, coelomic
epithelium that also covers all the organs.
3.
In the thorax, the coelom is divided into the pleural cavities and the pericardial cavity, which contains the
heart.
4.
In the abdominal cavity (also known as the peritoneal cavity), the coelomic linings are referred to as the
parietal and visceral peritoneum. The membranes that support the organs from the body wall are the
mesenteries, double sheets that are continuous with the peritoneum.
5.
Identify the lungs in the pleural cavity. Distinguish them from some thymus gland that may extend into this
cavity. The left lung is divided into three lobes, and, in the pig but not the human, the right into four lobes.
The trachea leads to the lungs via two major branches, the bronchi (‘bronchus’), which in turn branch in the
lungs into smaller and smaller air passages, finally ending in bronchioles that lead to the very thin-walled
alveoli (‘alveolus’). You may not see the bronchi well until the next lab, when you remove the heart, though
if you carefully lift the heart and lungs, you may see the bronchi branching from the trachea.
PADR.11
Anatomy of Pig Digestive and Respiratory Systems
6.
For now, cut out a lobe of the lung and use your scalpel to scrape away some of its wall. You can see many
blood vessels and branches of the bronchi.
7.
The alveoli are microscopic, so examine a prepared demonstration slide of a mammalian lung, and see
blood vessels containing red blood cells, bronchi, bronchioles, alveolar sacs, and individual alveoli. Capillaries, the smallest blood vessels just the diameter of a single red blood cell (8 μm), line the alveoli and it is
across these walls that gas exchange between blood and air occurs. Remember that the lungs of the fetus are
still filled with fluid, and so are dense. Make a drawing of the slide and answer the accompanying question
in the Report Sheet.
8.
Pull the left lung ventrally and toward the right side of the pig’s body to reveal the esophagus continuing
posteriorly from the neck region. Don’t confuse the esophagus with the dorsal aorta, the main artery of
the body, which lies against the back and is a tough, rubbery white cord, injected with red latex. Trace the
esophagus posteriorly through the diaphragm to the stomach.
9.
Examine the diaphragm, a broad, thick, dome-shaped muscle that separates the thoracic and abdominal
cavities.
10. Make sure you observe the lung demonstration of smoker vs. non-smoker lungs.
Part VI. The Major Organs of the Abdominal Cavity
Today you will investigate the organs of the digestive system and associated glands and organs. These occupy
most of the abdominal cavity. Next lab you will examine the organs of the circulatory, excretory, and reproductive
systems, which lie toward the posterior of the cavity. Always be careful not to cut major blood vessels, as these
will also be the subject of your next lab study.
The most conspicuous organ of the abdominal cavity is the large, brown, 5-lobed, liver, which has many functions: it secretes bile, which aids in the digestion of fats in the small intestine and in concert with pancreatic
lipase; it metabolizes carbohydrates, proteins, and fats brought to it in the blood stream; stores carbohydrates
(glycogen, or ‘animal starch’); synthesizes blood plasma proteins; degrades toxins; and removes damaged red
blood cells. Diseases of the liver include jaundice, hepatitis, and cirrhosis. We will return to the digestive functions of the liver below.
PADR.12
Anatomy of Pig Digestive and Respiratory Systems
1.
Pull the liver anteriorly to reveal the large, sac-like stomach in the left side of the peritoneal cavity. Protein
digestion is initiated here by the combined action of the enzyme pepsin and hydrochloric acid.
2.
Along the left side of the stomach, observe the spleen, a long, flattened, reddish-brown organ that helps
produce red blood cells in the fetus and in the adult stores and eliminates them.
3.
Cut open the stomach and wash out the contents. Even though the fetus does not yet feed, it may ingest
amniotic fluid, and the stomach contains mucus and sloughed-off epithelial cells, along with some bile. Note
the folds, or rugae, in the stomach wall, which serve to increase its surface area and allow for expansion with
a large meal.
4.
At the junction of the esophagus and the stomach, identify the thick cardiac sphincter, a muscular ring
that serves as a valve to prevent stomach contents from returning up the esophagus. When some of the acidic
contents do pass up the esophagus, we experience the sensation known as ‘heartburn’.
5.
At the other end of the stomach, near the small intestine, identify the even thicker pyloric sphincter, which
prevents food from entering the intestine until it is sufficiently digested in the stomach.
6.
The first part of the small intestine is the duodenum, which runs posteriorly and to the left, then recurves
anteriorly toward the stomach. Here the small intestine continues first as the jejunum and then as the
ileum, which becomes the colon, distinguishable as tightly bound coils of thicker tubing, finally descending
to the rectum and exiting the body at the anus. The rectum cannot be seen until later. Just before the small
intestine enters the colon, discern the caecum, a small blind sac that in rodents and horses houses a culture
of cellulose-digesting microorganisms. Our appendix lies at the end of a very short caecum.
7.
Cut open a section of the small intestine, wash it out, and notice the smooth, velvety lining, resulting from
the numerous intestinal villi, microscopic projections that increase the absorptive surface. Animals, such
as rabbits, that digest much plant food have relatively much longer caeca than we do.
8.
Observe the prepared slide of a transverse section of the small intestine of a mammal and identify, from
the lumen outward, the villi, microvilli, simple columnar epithelial cells, goblet cells, blood vessels
in the villi, and, peripherally, circular and longitudinal smooth muscle layers. Make a drawing of the slide
in the Report Sheet.
PADR.13
Anatomy of Pig Digestive and Respiratory Systems
9.
Returning to the duodenum, identify the highly nodulated tissue comprising the pancreas, which lies in
the mesentery in the loop of the duodenum. The pancreas contains both exocrine and endocrine tissue: it
secretes, through the pancreatic duct into the duodenum, enzymes that act on all major categories of food
(carbohydrates, proteins, lipids, and nucleic acids); and it secretes, into the blood, insulin and glucagon,
hormones that control carbohydrate metabolism. Insufficient insulin production leads to a form of diabetes.
10. Lift the liver and find embedded in its posteroventral wall (near where the umbilical vein enters the liver) a
conspicuous, light-colored sac, the gall bladder. The common bile duct empties into the duodenum. Bile
produced in the liver accumulates in the gall bladder until food enters the duodenum. Then bile is released to
aid in the digestion of fats and other nutrients. Although the bile contains no enzymes, it is highly alkaline,
neutralizing the acidity of the stomach acids and making conditions favorable for the action of pancreatic
and intestinal enzymes. Bile also contains salts that help to emulsify fats and pigments from the breakdown
of hemoglobin. Bile also contains much cholesterol, the precipitation of which can lead to the formation of
gallstones.
11. Know that many herbivores have very long colons, or large intestines, where cellulose digestion by resident bacterial ‘flora’ can take place, although much digestion occurs in the caecum.
PADR.14
Name:
Section:
Report Sheet:
Date:
Anatomy of Pig Digestive and Respiratory Systems
Background Questions
1.
Does the fetal pig eat? Where does it get its nourishment?
2.
Does the fetus breathe? How does fetal blood become oxygenated?
3.
Do the fetal kidneys function? How does the fetus eliminate metabolic wastes (‘urine’)?
4.
Does the fetal heart beat? How does fetal blood receive oxygen?
Catalyst Education OER Labs are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 license.
To access our full list of experiments visit https://links.labflow.com/OER. Lab Version PADR Release 3.28.
PADR.1
Anatomy of Pig Digestive and Respiratory Systems Report Sheet
Part I
Sex of pig
1.
What is the function of the nictitating membrane? (If you visit a zoo with flamingoes, carefully watch
their eyes: from time to time, they conspicuously ‘blink’ their nictitating membranes!)
2.
What is the function of mammae?
3.
What is the function of the anus?
Part II
1.
Describe the function of the following:
a. components of the saliva
b.
teeth
c.
ridges on the hard palate
d. soft palate
e. tongue
f. epiglottis
g.
esophagus
PADR.2
Anatomy of Pig Digestive and Respiratory Systems Report Sheet
Part IV
1.
Why might vocal chords be difficult to see in the fetus?
2.
What is the function of the supporting rings in the trachea?
3.
Why must the trachea remain open at all times?
4.
What is the function of the cilia?
5.
What is the function of the goblet cells?
6.
How does movement of food through the esophagus occur?
PADR.3
Anatomy of Pig Digestive and Respiratory Systems Report Sheet
7.
Prepared slide drawings:
Trachea:
Esophagus:
Part V
1.
After birth, the lungs fill with air and become light and spongy. How does this happen in humans?
2.
Make a drawing of the prepared slide of the mammalian lung:
3.
What does the diaphragm do?
PADR.4
Anatomy of Pig Digestive and Respiratory Systems Report Sheet
Part VI
1.
Why does heartburn appear to involve the heart?
2.
Make a drawing of the prepared slide of the small intestine:
3.
What is the function of the large intestine?
PADR.5