BIOL&242
Lab 38
Hand in labeled sketches, and answers to questions below with Lab 38. This lab requires 5 sketches.
Activity 2- Stomach and Esophagus
Esophagus (your book has you look at the gastroesophageal junction)
A. Draw and clearly label the esophagus at low power. Please try to squeeze the entire height of the
tissue into view! Label: the mucosa (yes, bracket the entire mucosa), and then within the mucosa, label:
the epithelia (label the TYPE of epithelia), lamina propria (label the TYPE of connective tissue), and
muscularis mucosae. Label the submucosa (note glands if seen), and muscularis externa (label the two
different muscle layers here).
Q1: For each layer of muscluaris externa, state which direction the fibers run, in relation to the
digestive ‘tube’.
Q2: What type of muscle would you expect to comprise the muscularis externa in the upper esophagus?
The lower esophagus?
Q3: What is acid reflux, or heartburn? Where does it occur along the digestive tract?
http://www.bu.edu/histology/p/10801ooa.htm
http://www.histol.chuvashia.com/atlas-en/digestive-01-en.htm
http://www.siumed.edu/~dking2/erg/GI014b.htm
Stomach- Fundic region (fundus)
Ideally, you should be sketching from the “body” or fundus of the stomach. If you choose the composite
slide, it contains three stomach regions. The first sample (left most) is from the fundus, the third sample
(right most) is from the pyloric region. Look at both samples, but 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.
-For the pyloric region of the stomach, think about where you would expect to find G cells.
Q4: What do parietal cells secrete?
Q5: What do chief cells secrete?
Q6: What do G cells secrete?
Q7: Do rugae involve the submucosa or mucosa or both (submucosa AND mucosa)?
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
Activity 3- Small Intestine
This is another composite slide. The three regions of the small intestine are presented on the slide in
order of appearance in the body. Please sketch the first region but be able to recognize all three!
-For the duodenum, label: epithelia (what type), goblet cells (if you see any), intestinal crypts (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.
Q8: Why does the duodenal region of the small intestine have so many Brunner’s glands?
Q9: There is a large collection of lymph tissue in the ileum region that battles bacterial infiltration. What
is this tissue called? Why is there likely to be bacteria here, in the ileum specifically?
Q10: Do plica involve the submucosa, mucosa, or both?
http://meded.ucsd.edu/hist-img-bank/chapter_6/Slide_93_gas-duo_junction/index.htm- gastro-duodenal
junction, super cool!
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
Activity 4- Large intestine
Sketch the large intestine (specifically the colon). Label the numerous goblet cells, and intestinal glands.
Q11: Do you see villi here? 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
Activity 8- 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.
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
http://meded.ucsd.edu/hist-img-bank/chapter_7/index.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)
For the quiz, you must be able to recognize and clearly label a small portion of the pancreas (yes, again).
Be able to label/recognize: a pancreatic acinus (a collection of acinar cells, all facing a shared lumen, or
duct), a lumen and a pancreatic islet.
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

Written
by Heidi Iverson, Ph.D.