Digestive System

Digestion (breakdown) and absorption of nutrients and water.

Organs of the Digestive System

Organs of the digestive system (in order of food encounter in the GI tract) include:

1. Mouth: breaks up food particles.

2. Salivary glands: create saliva to moisten and lubricate food.

   • Amylase digest polysaccharides.

3. Pharynx: swallows.

4. Esophagus: transports food.

5. Stomach: stores and churns food.

   • Pepsin digests protein.
   • Hydrogen chloride activates enzymes, breaks up food, kill germs.
   • Mucus protects stomach wall.
   • Limited absorption.

6. Liver: breaks down/builds up many biological molecules.

   • Stores vitamins and iron.
   • Destroys old blood cells.
   • Destroys poisons.
   • Bile emulsified fats and aids in lipid digestion.

7. Gallbladder: stores and concentrates bile.

   • Contains conjugated bilirubin.

8. Pancreas: creates hormones to regulate blood glucose levels.

   • Create insulin.
   • Reservoir for bicarbonate.
   • Trypsin and chymotrypsin digest proteins.
   • Amylase digest polysaccharides.
   • Lipase digests lips.

9. Small intestine: completes digestion.

   • Mucus protects gut wall.
   • Absorbs nutrients and most water.
   • Peptidase digests proteins.
   • Sucrase digests sugars.
   • Amylase digests polysaccharides.

10. Large intestine: forms and stores feces.

    • Reabsorbs some water and ions.

11. Rectum: stores and expels feces.

12. Anus: opening for elimination of feces.

Enzymes of the Digestive System

• Amylase.
• Pepsin.
• Lipase.
• Trypsin and chymotrypsin.