Digestion is the mechanical and chemical breakdown of foods into forms that your body cells can absorb. The organs of the digestive system carry out digestion and can be divided into two categories—those of the alimentary canal and accessory organs. Organs of the alimentary canal extend from the mouth to the anus. They are the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anal canal. The accessory organs include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas (Figure 331). You may find it helpful to review Figure 237 in Chapter 23 to review the abdominal regions and quadrants while studying the organs of this chapter.

Outline

• Characteristics of the Alimentary Canal
• The Mouth
• The Pharynx
• The Esophagus
• The Stomach
• The Small Intestine
• The Large Intestine
• The Rectum and Anal Canal
• The Liver
• The Gallbladder
• The Pancreas
• The Absorption of Nutrients

Learning Outcomes

After completing Chapter 33, you will be able to:

 33.1 List the functions of the digestive system.
 33.2 Trace the pathway of food through the alimentary canal.
 33.3 Describe the structure and functions of the mouth, teeth, tongue, and salivary glands.
 33.4 Describe the structure and function of the pharynx.
 33.5 Describe the swallowing process.
 33.6 Describe the structure of the esophagus and tell how it propels food into the stomach.
 33.7 Describe the structure and functions of the stomach.
 33.8 List the substances secreted by the stomach and give their functions.
 33.9 Describe the structure and functions of the small intestine.
 33.10 List the substances secreted by the small intestine and describe the importance of each.
 33.11 Describe the structure and functions of the large intestine, including the anal canal and rectum.
 33.12 Explain the structures and functions of the liver, gallbladder, and pancreas.
 33.13 List the substances released by the liver, gallbladder, and pancreas into the small intestine and give the function of each secretion.
 33.14 Tell what types of nutrients are absorbed by the digestive system and where they are absorbed.
 33.15 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the digestive system.

Summary