THE DIGESTIVE SYSTEM

Anatomy of the digestive system.

Click here for a diagram that summarizes the functions of the digestive system.

Another name for the digestive system is the alimentary canal. Here are some few important points to note:

1. Carbohydrate digestion begins in the mouth where the enzyme amylase is present. Amylase breaks down complex carbohydrates into simple sugars.

2. The tongue rolls the food into the ball-form called bolus.

3. Food travels down the esophagus by the peristalsis. This involves the rhythmic relaxation and contractions of the smooth muscles with forward propulsion.

4. The stomach secretes hydrochloric acid (HCl), mucus, and pepsinogen (an enzyme). Pepsinogen is activated to pepsin, which digest protein. Note: Protein digestion starts in the stomach.

5. The small intestine consist of the duodenum, jejenum, and ileum.

6. The Gall Bladder stores bile. Bile is the yellow-greenish substance produced by the liver.

7. Bile helps to emulsify fat.

8. The pancreas is both an exocrine and endocrine gland. As an exocrine gland, it produces digestive juices and enzymes.

9. Fat digestion starts in the duodenum.

10. Absorption of digested food occurs in the ileum (third part of the small intestine).

11. Villi are present in the small intestine. They increase the surface area for absorption.

12. The large intestine stores the feces and also absorbs water.