1. The Digestive System
The digestive system consists of an alimentary canal and several accessory organs.

2. The Digestive System
The digestive system mechanically and chemically breaks down food.
Mechanical digestion includes chewing and peristalsis.
Chemical digestion includes the use of enzymes.

3. The Digestive System Digestion = Big Little Food Nutrients
Nutrients = carbohydrates sugars
fats fatty acids + glycerol
proteins amino acids

4. The Digestive System
Essential nutrients are absorbed into the body and the unused waste material is excreted out of the body.

5. The Digestive System
The Alimentary Canal

6. The Digestive System The Alimentary Canal A. Wall Layers 1. Mucosa
Structure: composed of epithelial, connective, and smooth muscle tissue; mucus secreting glands present
Function: protection, absorption, secretion
2. Submucosa
Structure: composed of loose connective tissue; glands, blood and lymph vessels present
Function: nourishment

7. The Digestive System The Alimentary Canal A. Wall Layers
3. Muscular layer
Structure: composed of 2 layers of smooth muscle; circular and longitudinal shaped fibers
Function: movement
4. Serosa
Structure: composes the outer layer of the canal
Function: secretion of fluid to lubricate so tube can slide feely

8. The Digestive System
IV. The Oral Cavity

9. The Digestive System
V. The Teeth

10. The Digestive System
VI. The Pharynx

11. The Digestive System
VII. The Salivary Glands

12. The Digestive System
VIII. The Stomach

13. The Digestive System
IX. The Small Intestine

14. The Digestive System
X. The Large Intestine

15. The Digestive System
XI. The Liver

16. The Digestive System
XII. The Gall Bladder and Pancreas

17. Overview Salivary Glands (amylase) Oral Cavity Esophagus
Stomach (HCL and pepsinogen = pepsin)
Pancreas (lipase, amylase, trypsin, chymotrypsin, carboxypeptidase: pancreatic juice)
Blood (fatty acids, glycerol, amino acids, monosaccharides)
Small Intestine (peptidase, lipase, sucrase, maltase, lactase)
Liver/Gall Bladder (bile/bile salts)
Large Intestine
(bacteria = intestinal flora)
Blood (water, electrolytes, vitamins)
Rectum

18. The Digestive System Digestion = Big Little Food Nutrients
Nutrients = carbohydrates sugars
fats fatty acids + glycerol
proteins amino acids

19. Chemical Digestion and Nutrients
Carbohydrates
Uses in the Body:
used primarily to supply energy for cellular processes

20. Chemical Digestion and Nutrients
Carbohydrates
Dietary Sources:
- starch from grains and vegetables - glycogen from meats - monosaccharides from honey and fruits
Dietary Requirements:
- Varies among individuals - Depends on amount of physical activity, body size and metabolic rate.

21. Chemical Digestion and Nutrients
Carbohydrate Digestion (starch to monosaccharide)
Pancreas
Chemical digestion by pancreatic amylase (breaks down carbohydrates into disaccharides)
Mouth
Mechanical digestion
Chemical digestion by salivary amylase (breaks down carbohydrates into disaccharides)
Small Intestine
Chemical digestion by sucrase, maltase + lactase
(break down disaccharides into monosaccharides: sucrose…)
Stomach
Mechanical digestion
Small Intestine
Glucose absorbed into blood

22. Chemical Digestion and Nutrients
Lipids
Uses in the Body:
-supplies energy for cellular processes and for building cellular structures

23. Chemical Digestion and Nutrients
Lipids
Dietary Sources:
- saturated fats found in meats, eggs and milk - unsaturated fats found in seeds, nuts and plant oils - monosaturated fats found in olive, peanut and canola oils
Dietary Requirements:
- Recommended to be less than 30% of total calories - Depends on amount of physical activity, body size and metabolic rate.

24. Chemical Digestion and Nutrients
Lipid Digestion (fat to glycerol + fatty acid)
Liver/ Gall Bladder
Mechanical digestion by bile
(bile crystallizes into bile salts and aid in lipid breakdown)
Pancreas
Chemical digestion by pancreatic lipase (breaks down lipids)
Mouth
Mechanical digestion
Stomach
Mechanical digestion
Small Intestine
Chemical digestion by intestinal lipase (breaks down lipids)
Small Intestine
Glycerol and fatty acids absorbed into lymphatic system.

25. Chemical Digestion and Nutrients
Proteins
Uses in the Body:
- all cells in your body make proteins. In order to synthesize proteins, body needs a supply of amino acids (from food).
- enzymes, clotting factors, keratin of skin and hair, collagen of connective tissue, plasma proteins, muscle proteins, hormones and antibodies.

26. Chemical Digestion and Nutrients
Protein
Dietary Sources:
- meats, fish, poultry, cheese, eggs and cereals
Dietary Requirements:
- Between 60 to 150 grams per day - Depends on amount of physical activity, body size and metabolic rate.

27. Chemical Digestion and Nutrients
Protein Digestion (protein to amino acids)
Pancreas
Chemical digestion by trypsin, chymotrypsin + carboxypeptidase (break specific bonds between amino acids)
Stomach
Mechanical digestion
Chemical digestion by
HCl acid and pepsin  pepsinogen (breaks specific bonds between amino acids)
Small Intestine
Chemical digestion by peptidase (breaks specific bonds between amino acids)
Mouth
Mechanical digestion
Small Intestine
Amino acids absorbed