a. The digestive system is made up of the alimentary canal (food passageway) and the accessory organs of digestion.

The products of the accessory organs help to prepare food for its absorption and use by the tissues of the body. The main functions of the digestive system are:

(1) To ingest and carry food so that digestion can occur.

(2) To eliminate unused waste material.

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b. The alimentary canal is approximately 28 feet long in the adult and extends from the lips to the anus. It is composed of the organs listed below.

(1) Mouth (and associated glands).

(2) Pharynx.

(3) Esophagus.

(4) Stomach.

(5) Small intestine (and associated glands).

(6) Large intestine.

(7) Rectum.

(8) Anal canal and anus.

c. Refer to figure 1-1, an illustration of the digestive system, as you continue to read about the structure and function of each component.

Figure 1-1. The digestive system.