Digestive System 1

Digestive System

The Digestive System ["A man does not live on what he eats, an old proverb says, but on what he digests."  Jean Anthelme Brillat-Savarin, The Physiology of Taste: Or Meditations on Transcendental Gastronomy]

Objectives      

1. Describe stimuli and controls of digestive activity.

2. Describe the location and function of the peritoneum.

3. Define retroperitoneal and name the retroperitoneal organs.

4. Define splanchic circulation.

5. Indicate the importance of the hepatic portal system.

6. Describe the tissue composition and the general function of each of the four layers of the

alimentary canal.

7. Identify structural modifications of the wall of the stomach that enhance the digestive process.

8. Name the cell types responsible for secreting the various components of gastric juice and

indicate the importance of each component in stomach activity.

9. Describe stomach structure and indicate changes in the basic alimentary canal structure that

aid its digestive function.

10. Explain how gastric secretion and stomach motility are regulated.

11.  Identify and describe structural modifications of the wall of the small intestine that enhance the digestive process.

12.  Differentiate between the roles of the various cell types of the intestinal mucosa.

13.  Describe the function of local intestinal hormones and paracrines.

14.  State the role of bile in digestion and describe how its entry into the small intestine is regulated.

15.  Describe the role of the gallbladder.

16.  State the role of pancreatic juice in digestion.

17.  Describe how entry of pancreatic juice into the small intestine is regulated.

18.  List the major functions of the large intestine.

19.  List the enzymes involved in chemical digestion; name the foodstuffs on which they act.

20.  Describe the process of absorption of breakdown products of foodstuffs that occurs in the small intestine.

21.  Describe some of the structural and functional properties of smooth muscle.

Part 1: Overview of the Digestive System (pp. 852–858; Figs. 23.1–23.6)

A.    Digestive system organs fall into two main groups: the alimentary canal and the accessory organs.

1.     The alimentary canal, or gastrointestinal (GI) tract, is the continuous muscular digestive tube that winds through the body digesting and absorbing foodstuff; its organs include: the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

2.     Accessory digestive organs aid digestion physically and produce secretions that break down foodstuff in the GI tract; the organs involved are the teeth, tongue,

gallbladder, salivary glands, liver, and pancreas.