Laboratory Reproductive System Anatomy Lab Rectal Examination

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					Lab 11: Anatomy of the Digestive and Reproductive Systems Laboratory
The first part of this laboratory is intended to provide you w ith the basic anatomical features of
the digestive system. There will also be a couple of histological sections that you will need to look
at. The second part will introduce you to the major anatomical features of the reproductive
system. You will want to bring your book for this lab. Next week we will review the major
anatomical features of the cadaver and perform a reproductive physiology exercise.


Introduction to Anatomy of the Digestive a nd Reproductive Systems:

Most of the nutrients that we consume cannot be used in their existing state. Instead they must
be broken dow n into smaller components, deposited into the bloodstream for transportation to
the cells of the body. The digestive system has two anatomical subdivisions: the accessory organs
and the digestive tract. The accessory organs are various structures in the body that directly aid
in the breakdow n of food into stuff the body can absorb. The accessory organs of the digestive
tract include the teeth, tongue, salivary glands, liver, gallbladder and pancreas. The three
primary organs (liver, pancreas and gall bladder) are not part of the tube within the body, but
empty into the alimentary canal. The digestive tract is a tube extending from the mouth to anus
and includes the oral cavity, pharynx, esophagus, stomach, small intestine and large intestine.

TORSO MODEL:
Organs of the Digestive Tract:
        Most of the digestive tract (Saladin Fig 25.1) is located within the peritoneal cavity
(Saladin A7-A10; pg 36-40) of the abdomen. Along the dorsal wall of the abdomen, the parietal
peritoneum turns inward and forms a sheet of tissue called the dorsal mesentery, extending to
the digestive tract. This membrane then forms the serosa – that outermost tunic layer, or outer
covering of the stomach and most parts of the intestines. In some places it continues beyond the
digestive organ as a sheet of tissue called the ventral mese ntery, which may hang f reely in the
abdominal cavity or attached to the ventral abdominal wall. (You cannot see this on the models
but the yare nicely shown by Saladin Figure 25.3.)
        A long the lesser curvature of the stomach, the serosa of the anterior and posterior
stomach surfaces meet and continue as a ventral mesentery called the lesser omentum and
extends from the stomach to the liver (fig. 25.1). Along the greater curvature of the stomach, the
serosae form the greater omentum, which hangs loosely ove r the small intestine like an apron.
You cannot see either of these structures on the torso model – otherw ise the organs in the cavity
would not be visible. At its inferior margin, the greater omentum turns back on itself, passes
upward and forms serous me mbranes around the spleen and transverse colon. Beyond the
transverse colon, it continues as a mesentery called the mesocolon which anchors the colon to the
posterior abdominal wall.
        The importance of these membranes is to anchor the organs of the digestive tract within
the abdominal cavity. Think about what it would feel like if the organs were not anchored, but
instead were free floating. Would you ever want to jump up and dow n?

The Oral Cavity: The oral cavity serves many functions including ingestion, mastication, initial
chemical digestion, and swallow ing.
       Def ine each of the terms:
       Ingestion:
       Mastication:
       Digestion
The cheeks and lips retain food and push it between the teeth for mastication. Identify the upper
and lower lips. Why are the lips fleshy and soft? The tongue is a muscular, bulky organ designed
to manipulate food. Its surface is covered with stratified squamous epithelium and exhibits
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numerous bumps and projections called lingual papillae. Most of the lingual papillae are taste
buds. Review the information in chapter 16 for what these receptors look like and their
distribution across the surface of the tongue. The palate separates the oral cavity from the nasal
cavity. Its anterior portion is the hard palate (or bony palate) and is a bony projection of the
palatine processes of the maxillae and palatine bones (figure 9.4, page 255). Posterior to the
hard palate is the soft palate which has a spongy texture and is composed mainly of skeletal
muscle and glandular tissue. Clinically remembe r the discussion about the cleft palate? The soft
palate has a conical medial projection called the uvula -- the piece of tissue that hangs down in
the back of the mouth.
        Try talking without letting your tongue touch the hard palate, if you had Fetal A lcohol
syndrome or a congenital birth defect you might have been born without a hard palate or have
some cleft palate defect . Why is the hard palate so important for speech?
         An adult normally has 16 teeth in the mandible and 16 in the maxilla (32 total).
Collectively they are called the dentition. Review Saladin Fig. 25.5 and identify all tooth types: 8
incisors, 4 canines, 8 premolars and 12 molars, also be able to identify these on the teeth of a
actual human skull. What is the function of each tooth type? How might dental caries negatively
impact your ability to eat and digest food?
        The salivary glands (Saladin Figure 25.8) can be divided into two broad groupings called
the intrinsic and extrinsic salivary glands. The intrinsic glands are located within the oral tissue.
These glands secrete relatively small amounts of saliva at a fairly constant rate, keeping the
mouth moist and inhibiting bacterial growth. They also produce lingual lipase and lysozyme.
Lingual lipase is an enzyme that begins to break dow n lipids (i.e., fats). Lysozyme is an enzyme
that has some antibiotic properties.
        The extrinsic glands are the more obvious glands, and the ones you can see on the model.
These glands are situated outside the oral cavity. Locate the parotid gland, submandibular gland
and sublingual gland on the torso model. The parotid glands are just ventral to the ears and cover
the maxillary- mandibular joint. The submandibular glands are typically close to the medial side of
the mandibles and the sublingual gland is directly below the tongue.

When your doctor gently palpates under your jaw, he/she is attempting to tell if your glands are
swollen. If you have an infection, these glands may be enlarged. The best example of such
swelling is with the mumps w here t he parotid glands enlarge.

        The pharynx is a common passageway for the respiratory and digest ive system. It
extends from the dorsal extensions of the nasal cavity, past the posterior aspect of the oral cavity
and down towards the larynx. Identify this organ on the torso model. It is typically divided into
the nasopharynx, which includes the area just behind the nasal cavity; the oropharynx, the area
behind the oral cavity; and the laryngopharynx, just anterior to the larynx. It takes about 2
seconds for you to swallow food from the oropharynx to the stomach.
        The esophagus is a straight muscular tube that begins posterior to the larynx at the level
of the cricoid laryngeal cartilage and travels dow nward through the mediastinum of the thorax.
This is the majo r tube that allows food to enter into the stomach. The esophagus penetrates the
diaphragm at an opening called the esophageal hiatus and meets the stomach at the cardiac
orifice. This orif ice is surrounded by smooth muscle called the lower esophageal sphincter. Locate
the esophagus and its regions in the torso model. Note that it runs dorsal to the trachea. You
have actually seen this on the male cadaver as it extends down the thoracic cavity towards the
diaphragm.
        The wall of the esophagus is organized into the following tissue layers: Mucosa,
Submucosa, Muscularis Externa and Adventitia/Serosa. All organs have these tissue layers in very
similar patterns. Anatomically this is a unique structure because the esophagus starts as a tube
of skeletal muscle and makes a transition to all smooth muscle at the cardiac oriface .

If you had gastroesophageal reflux disease, where would you see the lesions? What contributes
to the lesions? When a pill is not swallowed properly with adequate water, it may get stuc k in the
esophagus and forms an adhesion to the both sides of the esophagus. The pill dissolves and
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injures the underlying tissues giving it a “kiss-like” appearance. Do a quick search on line for
“kissing ulcers” (nothing funky here ok?).

        The stomach is a muscular sac in the upper abdominal cavity immediately inferior to the
diaphragm. It is slightly J-shaped. The medial margin is called the lesser curvature and the longer
lateral surface is called the greater curvature.
        The stomach is divided into four regions: the cardiac region, the fundic region, the body,
and the antrum. Each region has a particular function and secretion. Based on figure 25.11,
identify each of the four regions of the stomach on the torso model. Draw a picture of the
stomach and label the four regions.

When you have gas, what part of the stomach “floats” and causes the discomfort? Why do they
call gastric gas “heart burn” sometimes? If you had an ulcerative lesion that eroded through the
stomach wall to the peritoneal cavit y, what would the outcome be?

These types of Gastric Bypass Surgery have beco me popular for weight loss. Here are some
different types that are discussed at
http://www.nlm.nih.gov/medlineplus/ency/article/007199.ht m




Roux-en-Y     Adjustable     Vertical     Biliopancreatic Biliopancreatic Dumping
stomach       gastric        banded       diversion       diversion with syndrome
surgery for   banding        gastroplasty (BPD)           duodenal
weight loss                                               switch


        Nearly all chemical digestion and nutrient absorption occurs in the small intestine. The
small intestine is divided into three regions: duodenum (about the first 8-10 inches), jejunum
(the middle segment and is about 2.5 meters long), and the ileum (the last 3.6 meter segment).
The duodenum begins pyloric sphincter and runs for “The first 12 fingers widths of the intestine”.
The jejunum is fairly non-descript, but is the middle segment of the intestine. The jejunum and
ileum are not separated by any conspicuous landmark, but the jejunum is typically located in the
upper left of the intestinal coils and the ileum to the lower right. Most nutrient digestion and
absorption occurs in the jejunum and ileum. The ileum ends at the ileocecal junction, where it
joins the caecum, the first part of the large intestine.
        The large intestine begins at the cecum, a blind pouch in the lower right abdominal
quadrant. (Saladin Figure 25.30) Attached to its lower end is the vermiform appendix. The large
intestine is subdivided into the ascending colon, the transverse colon and the descending colon.
The ascending colon begins at the ileocecal valve and passes up the right side of the abdominal
cavity. It makes a 90 degree turn at the hepatic flexure (bend close to the liver) and then
becomes the transverse colon. The transverse colon passes horizontally across the upper
abdominal cavity and turns downward at the splenic flexure (bend near the spleen). It now
becomes the descending colon which passes down the left side of the abdominal cavity. The
pelvic cavity is narrower than the adbominal cavity so at the pelvic inlet the colon turns medially
and downward, forming a roughly S-shaped portion called the sigmoid colon. In the pelvic cavity,
the large intestine straightens and forms the rectum. The final 3 c m of large intestine is the anal
canal.
        The muscularis externa of the colon is unusual in that its longitudinal fibers do not encircle
the colon. Instead this muscle layer is divided into three ribbon-like strips called teniae coli. These
small strips constrict and create little pouches called haustra. Locate these on the torso models.
        The colon has the unique distinction of having the greatest number of bacteria of any
section of the digestive system, this can be good or bad. The good, some of these bacteria
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actually create things we need like vitamin K. The bad, some of these bacteria take undigested
carbohydrates in things such as beans or broccoli and produce gas (flatus). Bacteria in this region
can also produce toxic materials that can be carcinogenic to the epithelial cells that line the colon.
Why is colo-rectal cancer relatively common? Why is it that diets rich in fiber (undigested fibers
attract water to make the stools large and soft) help protect against colo-rectal cancer? In
contrast diets rich in meat (have you ever smelled rancid meat?) are often associated with
increased risk of colo-rectal cancer? During your colo-rectal exam, your proctologist will look for
either obvious cancerous growths or pre-cancerous growths called polyps. If you have parents
who are older, they may be willing to share what this examination entails (ask them if you like).
If you had colo-rectal cancer and had a portion of your large intestine removed, how would your
digestive process c hange? How would this alteration affect bile salt recycling and production of
nutrients by the microflora?

What if you have “Irritable Bowel Syndrome” or “Crohn’s Disease”, would your reabsorption of
digestive secretions be normal? What would be the effect?

Accessory Organs of the Digestive System:
Several of the accessory organs have already been discussed when examining the oral cavity.
However the functions of the intestine rely on the actions of the larger accessory organs, in
particular the live r and pancreas.

Liver: The liver is the largest gland in the body. It is typically a reddish brown organ located
immediately inferior to the diaphragm and fills most of the right hypochondriac and epigastric
regions of the abdominal cavity. The liver has a diverse number of functions including the
secretion of bile that aids in fat emulsification and digestion. The liver also has an unusual ability
to regenerate if a section is removed, an important thing for transplant donation. Please don’t
try this with your heart or lung!
        The liver has four lobes called the right, left, quadrate, and caudate lobes. The right lobe is
the largest and the caudate lobe is the smallest. Using Figure 25.17, page 907, locate each of the
lobes of the liver on the torso mo dels. Note that the right and left lobes are separated from each
other by the falciform ligament. In the inferior aspect, locate the quadrate and caudate lobes. The
quadrate lobe is next to the gallbladder and the caudate is located next to the vena cava. Locate
the gallbladder on the inferior surface of the liver. You should also be able to identify the hepatic
portal vein, the hepatic artery and the common hepatic duct. What is a “portal” circulatory
structure? Compare and contrast the degree of blood oxygenation in each of these three blood
vessel types.

Gallbladde r: The gallbladder is a small greenish sac semi-embedded in the inferior surface of
the liver. The head of the gallbladder projects lightly beyond the liver and is more balloon-like.
The neck of the gallbladder is continuous with the cystic duct that joins with the hepatic bile duct
to become the common bile duct. The gallbladder is primarily a holding chamber for temporarily
holding the bile produced by the liver. When you digest foods the gall bladder contracts to expel
the stored bile into the intestine. Locate each of the above structures on the torso models.
Where do gall stones form and how do they create inflammation in the wall of the gall bladder
and sometimes jaundice?

Panc reas: The pancreas is a soft, spongy, pink gland that is posterior to the greater curvature
of the stomach and outside the peritoneal cavity. Remember that the pancreas produces exocrine
secretions that are critical for digestion. What ducts permit the exocrine secretions of the
pancreas to be drained? The pancreas also produces endocrine secretions such as insulin and
glucoagon. What do these two hormones do? Why is blockage of a pancreatic drainage a cause
for pancreatitis?




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Histology of the Digestive System

Mic roscopic anatomy of the Esophagus/stomac h transition (slide 28 from the dra we r)
This is a longitudinal section of the esophagus-stomach junction. So the first thing you need to
orient yourself to what you are looking at. Locate the mucosa laye r (the surface next to the
lumen). The esophageal mucosa consists of stratified squamous epithelium. Nearer to the
stomach junction there is a distinct muscularis mucosa layer. Both the mucosa and submucosa
form longitudinal folds that give the lumen an irregular outline. The submucosa is filled with
numerous glands that produce mucus to lubricate the surface of the epithelium. The submucosa
also contains numerous small blood vessels. The muscularis externa layer in the esophagus
transitions from skeletal muscle in the first 1/3, to a mix of skeletal and smooth in the middle
third and finally to simply smooth muscle in the distal 1/3 of the organ. You should be able to
identify two smooth muscle layers in the muscularis externa, an inner circular smoo th muscle
layer and an external longitudinal layer.
        At the gastro-esophageal junction the epithelium transitions from stratified squamous
(esophagus) to simple columnar (stomach). The inner surface of the stomach is organized into
longitudinal folds called rugae. Extensions of the mucosa and submucosa extend into the folds.
The muscularis externa layer has three smooth muscle layers, a circular layer, transverse and
longitudinal layer. This allows the stomach to have a wringing motion, the kind of motion one
does with a wash-cloth to get rid of the water. Compare slide 24 (Fundic Region of the Stomach)
with this portion of slide 28.

Mic roscopic anatomy of the small intestine: ( Slide number 5 from the dra wer)
The microscopic anatomy of the small intest ine includes modifications for maximizing digestion
and absorption, as well as glands and muscles to facilitate in this process (Saladin Figure 25.24).
If you were able to examine the surface of the mucosa, you would see that the surface is covered
by finger-like projections called villi. These function to increase the surface area of the mucosa.
Each villus is covered by simple columnar epithelial tissue (absorptive cells) with numerous goblet
cells interspersed in the layer. One the very surface of the epithelial cells are microvilli -- you
probably cannot see these with your microscopes. These microvilli have many proteins embedded
in their plasma membrane that function as digestive enzymes called the brush border enzymes.
The villus is filled w ith areolar connective tissue of the lamina propria. Embedded in this areolar
connective tissue is an arteriole, capillary network and a venule, as well as a lacteal -- a
lymphatic capillary. Between the bases of many of the villi are intestinal crypts. These crypts are
similar to the gastric glands of the stomach.
         The submucosa is characterized by numerous, predominant duodenal glands. Look for the
semi-circular structures that appear to be made of cuboidal epithelial tissue. These glands are
important in secreting bicarbonate-rich mucus. This mucus will neutralize stomach acid and make
the chyme ready for the digestive enzymes. The muscularis externa consists of a relatively thick
inner circular layer and a thinner longitudinal layer.
         Draw a picture of the cross-section of the small intestine. Label the epithelial tissue,
submucosa, muscular externa (both the longitudinal and circular layers), and serosa. What would
happen to your digestive physiology the duodenum, ileum or jejunum were removed?

Mic roscopic anatomy of the colon (large intestine) (slide 32 from dra wer):
Again your first task is to look at this slide on very low power and familiarize yourself with the
tunic layers. The epithelial layer (simple columnar E. T.) lines the lumen. Together with the
lamina propria and the muscularis mucosa (a very small smooth muscle layer that follows just
internal to the E.T.) make up the mucosa layer. The submucosa is filled w ith connective tissue
that extends into the villi of the colon. Finally, the muscularis e xterna layer has two smooth
muscle bands, the inner one is circular and the outer, much reduced in size and distribution is the
longitudinal layer.

Mic roscopic anatomy of a salivary gland (slide number 21 in dra wer):

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This slide is a composite of three tissue slices. Scan the slide and see if you can determine
differences in the sections. Isolate the middle, mixed gland slice, this is more than likely a
section of the submandibular gland. There are both musous cells and acinar cells. One one side
you should see a gland with numerous mucous cells – in fact the mucous cells make up most of
the tissue prep creating very light – almost cloud like cells. This is similar to the histology of the
sublingual gland (Fig.25.10, p.963). The other tissue slice wit h predominantly serous acinus is
the parotid gland. It is made up almost exclusively of acinar cells. You should be able to isolate
mucous cells, serous cells, C.T. stroma, and ducts.

Mic roscopic vie w of the Liver: (You will use slide 23 for this exercise.)
The liver parenchyma consists mostly of cuboidal cells called hepatocytes. These hepatocytes are
arranged in approximately 6-sided (hexagonal) cylinders called hepatic lobules (Saladin Fig
25.20). Scan the microscope slide at 4 power (low power) to get an appreciation for the slide.
Each lobule has a central vein passing through its core. This is not a true vein as in the vascular
system, but rather as a central blood-filled canal. The hepatic lobules are separated from each
other by a sparse connective tissue stroma. Locate a hepatic lobule on the slide. Where multiple
lobules come together you may find a hepatic triad. This structure consists of two blood vessels
and a bile ductule. Try and locate a triad. I w ill not ask you to identify individual vessels in the
triad.
        The hepatocytes form thin epithelial plates that fan out away from the central vein, like
the spokes of a wheel radiating from the hub of the tire. These plates are separated from each
other by blood-filled channels called hepatic sinusoids. This means that the hepatocytes are in
direct contact with blood. The blood vessels of the hepatic triad supply blood to the sinusoids and
the blood filters through the sinusoids around the hepatocytes to the central vein. From the
central vein blood ultimately flows into the right and left hepatic veins and leaves the liver.

Sometimes the liver turns harmless things into potent toxins by accident, this can happen if you
mix alcohol with acetaminophen(Tylenol), which can result in massive acute liver failure (this is a
major cause of liver failure and need for a liver transplant). Why might the cells surrounding the
sinusoid just before it enters the central vein by most likely to die form the acetaminophen
metabolites?

       The liver secretes bile into narrow channels called bile cannaliculi that are found between
the sheets of hepatocytes. The bile then passes into the hepatic ducts that ultimately lead to the
common hepatic duct. You cannot see these structures under the microscope except for the bile
ductule in the triad.

What is jaundice? What happens to liver function when you have jaundice as an adult? Why are
infants born with a trace of jaundice? Why does sunlight seem to help clear up jaundice in
infants?

Mic roscopic vie w of the pancreas: (you will revie w slide 20 for this exerc ise.)
You have actually looked at this slide before. Recall finding the islets of Langerhands. Now you want
to focus on the exocrine portion of the pancreas. This is actually the bulk of the cells (98%) in the
pancreas, excluding the islets. These cells serve an exocrine function, producing enzymes secreted in
the pancreatic juices.




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Structures of the Digestive System one should know for next exam
tongue               soft palate         hard palate          uvula                incisor
canines              premolars           molars               parotid gland        submandibular
                                                                                   gland
sublingual gland     nasopharynx         oropharynx           laryngopharynx       esophagus
stomach              lesser curvature    greater curvature    cardiac region of    fundic region of
                     of stomach          of stomach           stomach              stomach
body of stomach      antrum of           pyloric region of    pyloric sphincter    duodenum
                     stomach             stomach
jejunum              ileum               ileocecal junction   caecum               vermiform
                                                                                   appendix
ascending colon      hepatic flexure     transverse colon     splenic flexure      descending colon
sigmoid colon        rectum              anal canal           liver                right lobe of liver
left lobe of liver   quadrate lobe of    caudate lobe of      hepatic portal       hepatic artery
                     liver               liver                vein (associated     (associated with
                                                              with liver)          liver)
hepatic bile duct    cystic duct         common bile duct     gallbladder          pancreas
haustra of L.I.




Histology for next Exam

Know the epithelial tissues of all of the organs examined.
Know the tunic layers and what structures delimit each layer.
Know the specific smooth muscle layers in the muscular externa.
Know the cell types when identified with the slide (e.g., salivary glands)
With the S.I., be able to identify structures like the villi.

You should be able to recognize the esophagus from the longitudinal section of the esophagus -
stomach. Likewise you should be able to recognize the stomach from this same s lide.

You should be able to identify the specific salivary gland from the tissue description.

You should be able to recognize the liver from the slide and the pancreas from the slide.

At the liver, you should be able to recognize the vessels and ducts f rom the slide.




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REPRODUCTIVE SYSTEM MODELS:
MALE REPRODUC TIVE SYSTEM MODEL:

We will study the parts of this model in a sequence that follows the pathway of sperm through the
male reproductive system. We will begin with the site of sperm production, the te stis in the
scrotum. The scrotum is a skin-covered, muscular sac that contains the testes. A part of the
scrotum is shown on each half of the model. On the right half of the model, a part of the medial
partition between the testes is shown.
        Within the sc rotum, find the testes. The testis on the left side of the model is show n with
its surrounding membranes removed. The epididymis can be found superior and medial to the
testis on the same side of the model. It is held tightly against the testis by a complicated set of
membranes that surround both organs. The pink ductus deferens can be seen attached to the
inferior, medial tail of the epididymis.
        Next, find the spermatic cord. It is a complicated structure that contains the ductus
deferens, a network of veins and arteries and a nerve. All of these structures are bound together
by the same set of membranes that tie the testis and epididymis together. The spermatic cord
continues upward to the abdominal wall where it penetrates the inguinal canal, a reinforced
opening through the lower abdominal wall. On the left side of the model parts of the abdominal
wall are removed so that the passage of the spermatic cord, through the inguinal canal, can be
followed.
        The sperm-transporting structure within the spermatic cord is also the ductus deferens.
This tan muscular tube can be traced from its origin on the epididymis, through the spermatic
cord, through the inguinal canal and into the abdominal cavity. From the inguinal canal, trace it
across the superior surface of the urinary bladder, over the ureter and down the posterior surface
of the bladder to where it joins with the seminal vesicle and terminates in the prostate gland.
        Now split the model in half and remove the left side of the bladder and attached
structures. The seminal vesicles can be located on the posterior surface of the urinary bladder.
Each seminal vesicle is a multi-lobed gland, which is painted tan. Notice that their ducts join with
the ductus deferens. Inferior to the seminal vesicle, find the prostate gland. This organ is
positioned close to the bottom of the urinary bladder. The prostate gland is painted a dark red -
brown. Note that the urethra passes through it.
        The tiny ejaculatory duct does not show up well on this model. It originates where the
seminal vesicle and ductus deferens merge. This duct occurs entirely within the prostate gland.
Its termination in the urethra is shown inside the prostate gland.
        Now, let us find the three parts of the urethra. The prostatic urethra is easy. It is the part
of the urethra inside the prostate gland. Next, comes the membranous urethra. This term refers
to that short segment of the urethra between the prostate gland and the base of the penis. On
this model, it is painted a mottled yellow/orange. It is very short, approximately one-half inch
long. Finally, find the spongy urethra, that segment of the urethra inside the penis. Examine a
half of the entire model so that you are aware of the position of the base of the penis near the
prostate gland. The.spongy urethra traverses the entire penis through the blue-painted spongy
column.
        The penis originates with muscular attachments near the prostate gland. Note that it is
firmly anchored to the pelvis by ligaments. The expanded distal end of the penis is named t he
glans of the penis.
        To examine the penis in cross section put the two detachable pieces together. Three
columns of the blue and red erectile tissue are visible. The two superior columns are named the
cavernous columns. The inferior one, containing the urethra, is named the spongy column. Split
the penis model in half to see that the spongy column expands to form the glans.
        A good exercise, at this time, would be to trace the pathway of sperm from where it is
produced in the testes to where it exits through the penis. One possible difficulty you might
encounter is the role of the seminal vesicle. Sperm never pass through or enter this gland. It
merely produces a mucus secretion which contributes to the formation of semen. On the other
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hand, sperm cells do pass through the prostate gland. Can you figure out why that last statement
is true?

FEMALE REPRODUC TIVE SY STEM MODEL:

Use the independent plastic model (not torso model) for this section. Start on a sagittal section
view of one-half of the model. Plac e the inner piece in the correct position inside the outer piece.
Locate the urinary bladder, urethra and urethral opening. Next, find the uterus, vagina and
vaginal opening. Finally, locate the rectum and anal opening.
         With that orientation in mind, remove the inner piece from the true pelvis and combine it
with the other half model to study the uterus, ovary and uterine tube. Let us begin laterally at the
yellow-painted ovary. Two tubular structures pass from the ovary to the uterus. The pale pink one
is a ligament that helps support the ovary. The dark pink/red one, with the red expanded end, is
the uterine tube. The greatly expanded, funnel-like end of the uterine tube, which partly
surrounds the ovary, is called the infundibulum. Finger-like fimbrae can be seen attached to the
edge of the infundibulum.
         Next, consider the uterus which consists of three distinguishable parts. Superior to the
insertion of the uterine tubes is the fundus of the uterus. The middle part is called the body of the
uterus. To find the cervix of the uterus split the model in half. The cervix of the uterus is the
narrower part which protrudes into the vagina. The recessed grooves between the cervix and
vaginal wall (like a moat around a castle) are called fornices. Find the position of the anterior
fornix and the posterior fornix. Internally, note that the uterus shows two different textures and
colors. The inner striated zone, which is a darker red, represents the endometrium. External to
the endometrium is a lighter red layer called the myometrium. The smooth, pink,outermost layer
of the uterus is its serosa, called that because it is a serous membrane.
         Between the uterus and urinary bladder is a peritoneum-lined pouch called the
vesicouterine pouch. (This pouch is not open on the model.) Between the uterus and rectum, find
the rectouterine pouch. These two pouches are of medical signif icance because they are "low
points" for the drainage of abdominal cavity infections. Note that the rectouterine pouch can be
easily drained through the vagina by means of an incision in the posterior fornix.
         Now, reassemble the model so that we can examine the external genitalia. Note that both
the urethra and vagina open into a narrow space called the vestibule. Lateral to the vestibule are
two folds of skin. The inner, smaller folds are named the labia minora. Lateral to them are thicker
folds called the labia majora. At the anterior part of the vestibule, note a blue-painted structure
anchored to the pubic bones. This structure is the clitoris. Near the opening of the vagina, a
small, horizontal fold of mucous membrane represents the hymen.

OVARY MODEL:

This model represents a half ovary with an assembly of the stages of development of follicles. At
the middle bottom is a mature follicle which is in the process of ovulation: rupturing to shed its
ovum. The ovum is the yellow structure being extruded. To the left of the mature follicle is a
large, yellow, scalloped structure, a corpus luteum. It formed from a previously ovulated mature
follicle. Between the mature follicle and corpus luteum is one of three corpus albicans. These are
the remnant scars of previous copora lutea. To the left of the mature follicle are three medium-
sized, immature, secondary follicles that may someday become mature follic les.

REPODUCTIVE HISTOLOGY :

Re productive Endocrine Histology: Ovary slide (slide up at front of lab) (See Saladin Fig.
17.12 for drawing and Fig 28.14 for histology). What is the ma in hormone produced by the
granulosa cells of the ovarian follicle? (This hormone belongs to the estrogen group of
hormones.) _________________________ . If you look at the graph associated with the

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physiology instructions you will see that this hormone is the dominant one during the follicular
phase and is responsible for causing the LH surge.

        What hormone is produced by the corpus luteum? ____________________________
This is the hormone of pregnancy. Human chorionic gonadotropin (hCG) from the pregnancy test
physiology exercise is responsible for keeping these endocrine structures functional during the
first weeks of pregnancy while the placenta is growing. Later the placenta will secrete most of
the hormones associated with pregnancy. The home pregna ncy test we will see next week uses
hCG as the basis for determining if a person is pregnant.

      Draw a picture of a whole ovary. Show small and large ovarian follicles. Draw a circle
around one and label it. Label granulosa cells and an ovum. You will not see any corpus luteum.

Testis slide (slide # 12) (Saladin Fig. 17.12) The endocrine cells you need to focus on are
between the seminiferous tubules. They are called inte rstitial cells. What hormone do these
cells produce? _______________________________ Draw a picture of a section through the
testis. Draw a circle around and label a seminiferous tubule. Also label developing sperm cells
and interstitial cells.




                              Checklist for Reproductive models :


         Male mode l               Female mode l                  Ovary mode l

Scrotum                      Urethra                       mature follicle

Testis                       urethral opening              Ovum

Epididymis                   Uterus                        corpus luteum

ductus deferens              Vagina                        corpus albicans

spermatic cord               vaginal opening               secondary follicle

inguinal canal               Ovary

seminal vesicle              round ligament of uterus

prostate gland               uterine tube

ejaculatory duct             infundibulum of uterine
                             tube

prostatic urethra            Fimbrae

membranous urethra           fundus of uterus

spongy urethra               body of uterus

glans penis                  cervix of uterus


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corpus cavernosum   anterior fornix

corpus spongiosum   posterior fornix

                    Endometrium

                    Myometrium

                    Perimetrium

                    vesicouterine pouch

                    rectouterine pouch

                    Vestibule

                    labium minus

                    labium majus

                    Clitoris

                    Hymen--




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Description: Laboratory Reproductive System Anatomy Lab Rectal Examination