Adapted from Akkaraju,
Lab 9 – The Digestive System: Anatomy and Processes of the Digestive System
Objectives Checklist. After completion of this lab, you should be able to:
ο locate each of the organs of the ο be able to trace the pathway of food
digestive system on models and through the digestive tract and
textbook figures and their anatomical indicate what processes occur along
relationships to one another the way
ο understand the processes happening ο identify the location, composition
along the alimentary canal and function of the four major
histological layers found throughout
ο distinguish between the digestive
the digestive tract (mucosa,
tract and its accessory organs and
submucosa, muscularis, serosa)
know the major functions of each
ο explain the purpose of membrane
ο identify the products of each
adaptations such as villi and
accessory gland and where each
delivers its product(s) to the
digestive tract ο distinguish between longitudinal,
circular, and oblique muscles
I. Pre-Lab Activities. These activities are to be completed before coming to lab.
A. Processes of the Digestive System
1. Define the following processes happening of the digestive system:
B. Anatomy of the Digestive System
1. Organs of the Alimentary Canal and Accessory Glands: Label the
following diagram with the terms in the box.
Oral cavity Rectum
Salivary glands Liver
2. Oral Cavity: Label the following diagrams with the terms in the
Parotid gland Canines=C
Sublingual duct tonsils
Oral Cavity Root
3. Stomach: Label the following diagram with the terms in the box
Cardiac sphincter Rugae of mucosa
Cardiac region Circular layer of the
Fundic region muscularis externa
Body region Oblique layer of the
Pyloric region muscularis externa
Pyloric sphincter Longitudinal layer of the
Duodenum muscularis externa
4. Small Intestine and Large Intestine: Label the following
diagram with the terms in the box
Duodenum Transverse colon
Jejunum Descending colon
Ileum Sigmoid colon
Internal anal sphincter
External anal sphincter
C. The Histology of the Digestive Tract: Label the following diagrams using the terms in the box
Cross Section of
Cross Section of
II. Lab Activities. These activities are to be completed during lab.
A. Anatomy and Processes of the Digestive System
1. Find each of the organs that you labeled in the Pre-Lab Activity B on the models in the lab.
Remember, you will be tested using models!
2. Circle the organs in the text box that are considered accessory organs (food does not pass
through them, but they make product(s) which are delivered to the tract to help with digestion
Pancreas Small intestine Laryngopharynx
Liver Gall bladder Oral cavity
Colon Anus Salivary glands
Stomach Esophagus Larynx
Rectum Oropharynx Appendix
3. For each of the following accessory organs, describe its products (enzymes or other
secretions) and how the product gets into the digestive tract (part of the tract that it empties
accessory Products delivered to:
(where in the GI tract it
organ (enzymes etc.)
4. Use models to help you fill in the flow chart below showing all of the structures/organs that
food passes through as it moves through the digestive tract. After you complete the flow
chart, lightly shade the boxes where the pH is acidic. Next, write the name of the
appropriate accessory organs in the spaces to the left and write the name(s) of the products
that each produces above or below the arrow (see example).
salivary amylase, oral cavity
5. Use the information you summarized in the Pre-Lab Activity A.1 table. and in the previous
exercise, to fill in the table below. Find in the models (dissected pig?) all the organs you list
in the table below.
Process List ALL -when applicable- the organs where this process happens
6. Describe mechanical digestion. Where does it occur? What structures are responsible for
7. Describe chemical digestion. What is responsible for chemical digestion?
8. Fill in the following table with a summary description of the major function(s) of each organ.
large intestine (colon)
9. Where does chemical digestion begin? Where in the digestive tract does the majority of
chemical digestion take place?
10. Where does absorption begin? Where in the digestive tract does the majority of absorption
11. What is the primary function of the large intestine? Why is this important?
12. Mucus is secreted everywhere along the digestive tract. What purpose does it serve? Why
do you think that the number of goblet cells (produce mucus) is so much higher in the large
B. The Histology of the Digestive Tract
1. The type of epithelium varies through the digestive tract. Fill in the table with the
appropriate type of epithelium and the purpose that it serves.
Epithelial Type Where Found Purpose
oral cavity, upper
small and large
2. While most of the digestive tract has two layers of muscle in the muscularis externa
(longitudinal and circular), the stomach has a third oblique layer. Based on what you
know about the role of the stomach in both mechanical and chemical digestion, why
do you think the stomach has this third layer?
3. Which part of the digestive tract has villi? How are villi different from microvilli?
What purpose does each one serve?
4. Gather slides of the different organs of the digestive tract and identify each of the
layers (mucosa, submucosa, muscularis, serosa) in each using low or medium
magnification. After you identify the mucosa, change to high magnification and
sketch what you see. Use your book to help you identify structures (villi, glands,
crypts, etc.). To review these tissues, you can use an online histology tutorial (e.g.
Organ Sketch Organ Sketch
esophagus slide # 32
slide # 30 (composite of all
slide # 31
slide # 33
C. Viewing Station
Go to the laptops in the viewing station and watch the following short videos:
1. Ingestion (See epiglottis in action at the beginning of the video!):
2. Rugae of the stomach: http://www.youtube.com/watch?v=Ln09qihUi3g
3. Peristalsis in Stomach: http://www.youtube.com/watch?v=YH3U_SLp9G0
4. Peristalsis in Stomach: http://www.youtube.com/watch?v=pJCjDtfhsCI
5. Peristalsis in Duodenum and Jejunum:
6. Segmentation in Jejunum: http://www.youtube.com/watch?v=PfnKvErPwY4