Digestive System Overview

1. Introduction:

   • Digestion begins once food enters the mouth.
   • Teeth perform mechanical digestion by breaking food into smaller pieces.
   • Saliva contains enzymes to begin breaking down carbohydrates.

2. Swallowing:

   • Once mixed and softened, the tongue pushes food to the back of the mouth for swallowing.

3. Esophagus:

   • Food enters the esophagus, where peristalsis propels it toward the stomach.

4. Stomach:

   • In the stomach, gastric juices (acid and enzymes) break down proteins.
   • Churning motion turns food into chyme, which takes several hours to form.

5. Small Intestine:

   • Chyme moves into the small intestine.
   • The first segment, the duodenum, mixes food with bile from the liver and pancreatic enzymes for further breakdown.
   • Nutrients are absorbed through villi into the bloodstream.

6. Large Intestine:

   • Remnants including fiber, water, and waste move to the large intestine.
   • Water is absorbed, solidifying the stool.
   • Bacteria further break down particles.

7. Rectum and Anus:

   • Waste material becomes stool and moves to the rectum.
   • Anal sphincters control the release of stool through the anus.
   • Waste removal completes the digestion process after nutrient absorption.