1. The Digestive System

2. Functions Ingestion Mechanical digestion Chemical digestion Movements
Absorption
Elimination

3. Mouth

4. Teeth

5. Pharynx & Esophagus
Both oropharynx and laryngopharynx
Esophagus

6. Stomach

7. Gastric Secretions
Mucus
HCl
Intrinsic factor
Pepsinogen
Gastrin

8. Regulation of Gastric Secretion
Cephalic
Gastric
Intestinal
Stomach emptying
4 hours
Liquids and carbs move out fast
Proteins and fatty acids take longer

9. Small Intestine Functions Finishes digestion Absorbs nutrients
Passes waste to large intestine

11. Small Intestine Secretions
Neutral/alkaline fluid
Mucus
Peptidase
Maltase, sucrase, lactase
Lipase
Secretin & cholecystokinin

12. Large Intestine

13. Large Intestine Functions
Absorption of fluids and electrolytes
Waste elimination

14. Liver Produces and secretes bile Bile salts
Many other non-digestive functions including: plasma proteins, storing glucose, detoxification of blood, and biomolecule metabolism

15. Gallbladder
Stores and concentrates bile

16. Pancreas Endocrine function for glucose homeostasis
Digestive functions:
Amylase
Trypsinogen/trypsin
Lipase

17. Chemical Digestion
Breaks down complex molecules into smaller ones that can be absorbed by cells
Uses the process of hydrolysis

18. Carbohydrate Digestion
Begins in the mouth
Polysaccharides are broken down to disaccharides
In the small intestines, disaccharides are broken down into monosaccharides – glucose, fructose, and galactose

19. Protein Digestion Begins in the stomach
Breaks proteins into polypeptides
In the small intestines, peptides are reduced to amino acids (the building blocks of proteins)

20. Lipid Digestion Only occurs in the small intestine
Fats are emulsified by bile to decrease attraction between the molecules
Lipids are broken down to monoglycerides and fatty acids (the building blocks of lipids)

21. The Bottom Line We ingest approximately 10 liters of materials a day.
9 liters or more are absorbed in the small intestine.
A meal takes approximately hours to make a complete journey through the digestive tract.