The Structure of the Digestive System

Activity Overview

At the beginning of a unit on the digestive system, it's important for students to have a foundation of which organs are involved and their function. In this activity, students will label a model of the digestive system. They should include a description of what happens at each stage in the process along with the label. To scaffold this activity, consider providing a list of organs and having students place arrows pointing toward the correct organ.

Digestive System Diagram Example

Stage	Description
Mouth	Food enters the alimentary canal through the mouth. It is chewed by teeth which break food down into smaller pieces. The food is mixed with saliva that contains enzymes.
Esophagus	The fibromuscular tube connecting the mouth to the stomach is called the esophagus. Food is pushed down using a wave-like muscular motion called peristalsis.
Stomach	The stomach is the muscular organ where food is mixed with gastric juices. Gastric juice has a low pH, meaning it is acidic, and is used to help digest food and kill potentially harmful bacteria.
Liver	In the digestive system, the liver produces bile which helps with the digestion of fats and oils.
Gallbladder	The gallbladder is where bile is stored and concentrated.
Pancreas	The pancreas is where biological catalysts called enzymes are produced. Digestive enzymes speed up the breaking down of large nutrient molecules.
Small Intestines	The small intestines are made up of three parts: the duodenum, the jejunum, and the ileum. Here, food is mixed with digestive enzymes and bile. The enzymes speed up the digestion process. Nutrients are then absorbed into the bloodstream.
Large Intestines	The large intestines are made up of two parts: the colon and the rectum. In the colon, water is reabsorbed from the food. Feces are stored in the rectum until they are ready to be passed.
Anus	Feces leave the alimentary canal through the anus.

Template and Class Instructions

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