DIVISIONS OF THE DIGESTIVE SYSTEM
The two divisions of the digestive system are the ali-mentary tube and the accessory organs (Fig. 16–1). The alimentary tube extends from the mouth to the anus. It consists of the oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine. Digestion takes place within the oral cavity, stomach, and small intestine; most absorption of nutrients takes place in the small intestine. Undigestible material, pri-marily cellulose, is eliminated by the large intestine (also called the colon).
The accessory organs of digestion are the teeth, tongue, salivary glands, liver, gallbladder, and pancreas. Digestion does not take place within these organs, but each contributes something to the digestive process.