Digestive Anatomy Lab

In-Lab Exercises

I have included the word list in this document. Any descrepencies between this document and the “wordlist”, you should default to this document. There is a lot of repetition on the wordlists. It is best to compare how different models show the same thing! The order is not important. Study models as they are available!

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Step 3. Study the Oral Cavity and Neck Region on Sagittal head models, the Torso, and images of the oral cavity We will compare two models: “Sagittal section of head” (Image A and B) and “Torso Model” (Image C). Notice that the sagittal section is giving you a medial view, while the torso is

giving you a lateral view.

Cavities:

Oral cavity Oropharynx Pharynx vestibule

Hard palate Soft palate Uvula

Esophagus (look near the stomach on the torso) Gingivae Incisor Neck Enamel Crown Lingual & buccal surface

Tongue Salivary glands: Parotid, submandibular and sublingual NOTE: Regarding the “sagittal head”, model: Parotid and submandibular can only be seen on the sagittal head that is on a stand! Look at “lateral side” of the model. All 3 tonsils

Compare these structures on both models, or indicate where they would be (many are not visible on the torso model, depending on which torso model is in the room).

Find all of them on the torso model.

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Image C

Image A

Image B

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#3

#4

#5

On Image B, ID the oral cavity, vestibule, oropharynx, vestibule, and the lingual & buccal surfaces of the teeth. Identify all the tooth types, & the gingiva. Note the occlusal surface. Notice the cusps. Look in your partner’s mouth. Using Image C, ID the raphe, which I will test off an image. Now, have them raise their tongue. ID the Lingual frenulum and openings of the ducts of the submandibular gland (green arrows on Image D)

Also, off Image E, be able to ID the 3 papillae marked with red arrows. Then, label the tongue drawing below. Notice you cannot see the sulcus, circumvallate papillae and lingual tonsil without a tongue depressor.

Compare the structures labeled on image A to the photo in image B and the sagittal head model. Label them on the photo. Sometimes this image, or a similar one, is on the exam.

Image A Image B

Image C

Image D

Image E

Step 4. Study the Jaw and Teeth models

Notice that the jaw opens to reveal the roots!

Gingivae Incisor Canine Premolar (bicuspid) Molars Neck Crown Root

Enamel Dentin Pulp Root canal Apical foramen Pulp cavity Occlusal surface Cusp Periodontal ligament

If not visible on jaw model, know from image!

Be able to ID all teeth individually!

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Step 5. Study the stomach, pancreas, duodenum

and spleen models

Sometimes the stomach models have the pancreas and other organs attached (image A), sometimes not (all other images). Looking at the “outside of the stomach model”, know all the regions and curvatures, the layers (visceral peritoneum, circular muscle, oblique muscle, and the mucosa, which you can see best at the pyloric sphincter). You cannot see the horizontal muscle layer easily. The big nerve is the vagus nerve. Then, open up the stomach model. This is a frontal section. Notice that the part you removed is not in correct anatomical position; be careful during the exam! Make sure you say these organs on the torso model. Use the word list for all the rest:

Spleen Splenic artery & vein

Stomach Body Fundus Cardiac region Greater& lesser curvatures Cardiac valve/junction Pyloric Pyloric sphincter valve Rugae

Duodenum Plicae circulares Pancreas

Head & tail Pancreatic duct Major pancreatic papillae & the hepatopancreatic ampullae Common bile duct

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Image A

Step 6. Study the liver model

Study both the large model, and a liver from the torso model. Everything on the wordlist can be found on the large model. Determine which direction is “posterior” or “caudal”. This will help you find the caudal lobe, which is easier to define on the torso’s liver. Study the accompanying image to understand the three ligaments. Use this when studying the model.

Caudate lobe Right lobe Left lobe Quadrate lobe Gall bladder Cystic duct R. Hepatic duct L. Hepatic duct Common hepatic duct Bile duct Inferior vena cava

Hepatic portal vein Hepatic artery Hepatic veins dumping into vena cava Ligamentum teres:

(round ligament) – HINT: it is on the inferior view! See accompanying image. This is where the umbilical cord entered the vena cava as a fetus!

Falciform ligament

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Step 7. Study the intestinal villus model

Warning! We have 2 intestinal villus models. One shows Peyer’s patches (shown), the other does not! Know both models, just in case!

Lumen Villus Goblet cell Lacteal Mucosa Muscularis mucosa Submucosa Muscularis (both layers) Serosa Capillaries in mucosa Arteries and Veins in Submucosa Intestinal crypt Plexus – both submucosal and myenteric Duodenal glands (if visible) Peyer’s patches (if visible)

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Serosa not in image

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Step 8. Study the slides!

Slide of Fungiform or Circumvallate papillae/Taste Bud at low power, or holding slide up to light. A= papillae, B = Taste bud.

Follow these steps:

At low power:

Either Fungiform or circumvallate papillae (A) Taste bud (B)

At higher power:

Taste bud Gustatory cell Gustatory pore Gustatory hair

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A

B B

A

B B

Taste bud slide

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#2

First study the accompanying image of the mucosa of the stomach (Image A). Look at the slide at low power, noting the mucosa and submucosa. Notice that the mucosal lining has a “table-top” look, flat on the top, indicating that you are looking at stomach glands, as opposed to villi in the small intestines (insert image). Now zoom in (Image C). Notice the pit and glands. Know where Mucous neck cells, Chief cells and Enteroendocrine reside on the slide

Mucosa Submucosa Gastric pit Gastric glands Know where Mucous neck cells, Chief cells and

Enteroendocrine reside on the slide

A

Frog Stomach slide

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B

of duodenum

C

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First study the accompanying image of the tissue layers of the duodenum at low power (Image A). Find the lumen. Notice the villi in the mucosa and duodenal glands (Brunner glands) in the submucosa. Can you pick out the 2 muscle layers in the muscularis externa? Then study the higher power slide (Image B). Find the lumen. See the villa? Simple columnar epithium? Goblet cells? How about the crypts? OK..how about the muscularis mucosa?

Now look back at Image A. See the muscularis mucosa? Then study the Ileum slide at low or medium power (Image C). Find the lumen. Noticed I have zoomed in on the mucosa. See the villa? Simple columnar epithelium, with a pretty obvious brush border? Goblet cells? Do you see the obvious Peyer’s patches (lymph nodes) in the submucosa and mucosa?

Then know on slide:

Duodenum/Ileum slide – low power or high power

Lumen Mucosae Submucosa Muscularis mucosa Muscularis externa Serosa Columnar cells Goblet cell Villi Microvilli Duodenal glands in Duodenum Intestinal crypts Peyer’s Patches in Ileum

Image A

Small Intestines: Duodenum and Ileum

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Image B zoom

Image C