The Digestive System

This system consists of the organs directly concerned in the reception and digestion of the food, its passage through the body, and the expulsion of the unabsorbed portion. These organs are conveniently grouped under two heads, viz.: (1) the alimentary canal; (2) the accessory organs.

The alimentary canal (Tractus alimentarius) is a tube, about 100 feet (ca. 30 m.) in length in the horse, and extends from the lips to the anus. It has a complete lining of mucous membrane, external to which is an almost continuous muscular coat. The abdominal portion of the tube is largely covered with a serous membrane—the visceral peritoneum. The canal consists of the following consecutive segments:

1.

Mouth.

2.

Pharynx.

3.

Œsophagus.

4.

Stomach.

5.

Small intestine.

6.

Large intestine.

The accessory organs are the teeth, tongue, salivary glands, liver, and pancreas.