Download ANP214-Summer 2006

BIOL&242
Name __________________________________
Lab 38
This is a modified version of the original Lab 38 Handout. Please follow the instructions below. If a sketch is
required, a space is provided for your work. This is all you need to hand in for Lab 38, no lab pages are
required.
Esophagus
Human Esophagus, Total Magnification 100x
Label the above image of the esophagus with the six terms below (please label with JUST the letters). Labels
will probably require brackets, to clearly show which region or structure is indicated (one bracket has been
provided for you, as an example).
A. Mucosa
B. Submucosa
C. Muscularis externa
D. Stratified squamous epithelium E. Lamina Propria
F. Muscularis mucosae
Q1:
The image above is from the superior one third of the esophagus, thus the muscularis externa is
a. skeletal muscle
b. smooth muscle
c. an equal mixture of skeletal muscle and smooth muscle
Esophagus and Stomach. Let’s first look at them together (they are connected you know!)
Here is a good, low power look at the esophagus-gastric connection, with description:
http://medpics.ucsd.edu/index.cfm?curpage=image&course=hist&mode=browse&lesson=34&img=593
Here is a high power link, with description. Nice!
http://medpics.ucsd.edu/index.cfm?curpage=image&course=hist&mode=browse&lesson=34&img=594
Hopefully in both images you noticed the abrupt change in the epithelium when moving from the esophagus (on
the left) to the stomach (on the right). I also think the low power image is helpful in seeing the thickness of the
muscularis externa.
Q2: Acid reflux (GERD) occurs HERE at this very junction, when gastric juices move “backwards” from the
stomach into the esophagus. What protection from stomach acid does the esophagus NOT have, that the
stomach has?
a. keratinized, stratified squamous epithelium
b. ample lymphatic tissue
c. a mucous membrane
d. goblet cells that make alkaline mucus
e. hair and natural flora
Stomach- Fundic region (fundus)
At 400x total magnification:
http://medpics.ucsd.edu/index.cfm?curpage=image&course=hist&mode=browse&lesson=34&img=596
At 40x magnification:
http://medpics.ucsd.edu/index.cfm?curpage=image&course=hist&mode=browse&lesson=34&img=595
Before you sketch the stomach lining, pause for a moment and “play along” with this “tour” of the stomach.
Imagine you are very, very small--small enough to walk along the stomach wall surface. As you walk along the
stomach, headed towards the small intestine, there is very little elevation change on your journey. Your walk is
mostly flat, with gently, rolling bumps along the way (perhaps it looks a bit like the grey matter of the brain).
As you walk, you must avoid falling DOWN, INTO holes. These holes lead down into gastric pits (which lead
to deeper gastric glands). As you walk along, avoiding these pits, note that the pits are “bubbling” over with
gastric juices and secretions.
Sketch and clearly label the fundus region of the stomach.
-For the fundus, label: epithelia (what type), gastric pits, gastric glands, the thin muscularis mucosae,
submucosa, and external muscularis layers. Indicate the area in the tissue where you expect to find parietal and
chief cells.
Sketch here:
Q3: What do parietal cells secrete? __________________________________________
Q4: What do chief cells secrete? _________________________________________
Q5: What do G cells secrete? _________________________________________
Q6: Do rugae involve the submucosa or mucosa or both (submucosa AND mucosa)? ___________________
Here are some additional images of the stomach.
http://www.bu.edu/histology/m/t_diges2.htm
http://www.pathpedia.com/education/eatlas/histology/stomach/Images.aspx
http://meded.ucsd.edu/hist-img-bank/chapter_6/index.htm
Small Intestine
The small intestine has three regions, the duodenum, jejunum and ileum. You have seen the ileum before- we
looked at the ileum during the lymphatic lab to find Peyer’s Patches. So, since we have seen the ileum before,
we will look at the duodenum and jejunum. You will only sketch the duodenum.
Before you sketch, imagine you are very small, once again. And now you are walking along the small intestinal
wall. This journey is a very challenging one, one of endless climbing and descending. The wall is highly
folded. And, protruding up from the folds are 400-500 million villi (you could think of each villus, singular, as
a finger of a dishwashing glove). Then, each “finger” is lined by columar epithelium, with cells that have
microvilli! (this is like covering the glove fingers with shag-carpet). Again, imagine trying to walk over the
microvilli, of the villi, of the wall-folds!! Exhausting. The wall isn’t for climbing, it is designed to have
maximal surface area to promote ABSORPTION of nutrients!
Links: http://medpics.ucsd.edu/index.cfm?curpage=image_directory&course=hist&mode=browse&lesson=34
INDEX of unbelievably nice (and labeled) images- Digestive system. Start with the first “small intestine” link,
and take a look around.
-For the duodenum, label: epithelia (what type), goblet cells (if you see any), intestinal crypts (also called the
crypts of Lieberkuhn), Brunner’s glands (these are large glands of the submucosa, also called duodenal glands),
and a villus. Although difficult to see, point/indicate where you would find a lacteal.
Q7: Why does the duodenal region of the small intestine have so many Brunner’s glands?
_________________________________________________________________________
Q8: There is a large collection of lymph tissue (Peyer’s patches) in the ileum region that battles bacterial
infiltration. Why is there likely to be bacteria here, in the ileum specifically, versus the jejunum?
__________________________________________________________________________
Q9: Do plica involve the submucosa, mucosa, or both?_____________________________________
Q10: What is in a lacteal? ___________________________________________________________
More to look at- Jejunum- Ileum junction (with Peyer’s Patches)
http://eugraph.com/histology/digest/digeimag/Peypat100.jpg
http://www.bu.edu/histology/p/11501ooa.htm
http://www.bu.edu/histology/p/11601oda.htm
http://www.histol.chuvashia.com/atlas-en/digestive-02-en.htm
Large intestine
Take a look around the colon (a portion of the large intestine) but you do not need to sketch. See the numerous
goblet cells, and intestinal glands.
Q10: List all of the subdivisions of the large intestine: ____________________________________________
________________________________________________________________________________________
Q11: Do you see villi here, in the colon? Yes or no? _______________________________________
http://pathology.mc.duke.edu/research/Histo_course/smallbowel.jpg
http://pathology.mc.duke.edu/research/Histo_course/colon.jpg
http://pathology.mc.duke.edu/research/Histo_course/colon6.jpg
Liver
Sketch and clearly label the liver. Identify and label (approximately) three lobules. For each lobule, label the
central vein, portal area (hepatic triad), and hepatocytes.
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/liver/histo_lobule.html (look at second image)
http://www.ouhsc.edu/histology/Glass%20slides/88_01.jpg
Q12: What three vessels/ducts are present at the portal triad? ________________________________________
Think about what fluid is found in each of the above vessels/ducts and which direction the fluid is traveling
inside of these vessels.
http://www.bu.edu/histology/m/t_liverg.htm
Pancreas (yes, you’ve seen this slide before, so, no, you do not NEED to sketch it again, but you may want
to take a look at it)
Recall that most of the pancreas is pancreatic acinar cells. The pancreas also contains pancreatic islets.
Q13: Which of these structures (acinus and pancreatic islet) is endocrine in function, which is exocrine?
__________________________________________________________
http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/pancreas/anatomy.html
http://www.bu.edu/histology/p/10403ooa.htm
Assorted last questions to answer:
Gland Matching – Match the gland from the right with the function/location on the left. Use each answer only
once.
_____1.
_____2.
_____3.
_____4.
_____5.
_____6.
Produce(s) mucus; found in the submucosa of the small
intestine
Produce(s) a product containing amylase that begins starch
breakdown in the mouth
Produce(s) a spectrum of enzymes and an alkaline fluid that is
secreted into the duodenum
Produce(s) bile that it secretes into the duodenum via the bile
duct
Produce(s) HCl and pepsinogen
Found in the mucosa of the small intestine; produce(s)
intestinal juice
a. duodenal glands
b. gastric glands
c. intestinal crypts
d. liver
e. pancreas
f. salivary glands
Q14. What is the gallbladder’s job? ____________________________________________________
Q15. What is the primary job of Kupffer cells of the liver? __________________________________