1. Digestive System and Nutrition
Organs Process of Digestion Nutrition

2. Path of Food through the Digestive System
mouth
pharynx
esophagus
Produces pepsin, HCl
Produces peptidases, maltase, lactase
stomach
small intestine
large intestine
anal canal
Peristalsis: Muscular contractions that move food through the digestive system

3. Accessory Organs and Glands
Produce salivary amylase
salivary glands
Produces pancreatic amylase, trypsin, lipase
Produces bile
liver
gall bladder
pancreas
Stores bile

4. Process of Digestion and Absorption
Mouth
Teeth chew food into smaller pieces
Salivary amylase (enzyme in saliva) begins starch digestion
Tongue mixes food with saliva to form bolus to be swallowed
Starch in bun has been broken into smaller chains of sugars

5. Process of Digestion and Absorption
Stomach
HCl acid unfolds proteins
Pepsin (enzyme) begins protein digestion, breaking some peptide bonds
esophagus
sphincter
pyloric
sphincter
muscularis
layer has
three layers
of muscle
mucosa layer
has rugae
gastric pit
gastric gland
Protein in beef has been broken into smaller chains of amino acids
cells that
secrete
gastric
juice
Contains pepsin, HCl, mucus

6. Process of Digestion and Absorption
Small Intestine
Large surface area due to numerous villi
Bile emulsifies lipids
Pancreatic and intestinal enzymes digest carbohydrates, lipids, proteins
Amino acids and sugars absorbed into blood
Lipids absorbed into lymphatic system
villus
lacteal
blood
capillaries
venule
arteriole
lymphatic
vessel
Carbohydrate, Protein and Fat have been digested and absorbed

7. Digestion occurs by Hydrolysis of Macromolecules
Emulsification: physical dispersion of lipids into smaller droplets
carbohydrate
protein +
Hydrolysis: chemical separation of subunits
pancreatic amylase
bile salts
fat globules
trypsin
emulsification
droplets
peptides
maltase
hydrolysis
cell of
intestinal
villus
peptidase
lipase
Hydrolysis
glucose
amino acids
pH = basic
pH = basic
pH = basic
lymphatic
capillary
blood capillary
blood capillary
Carbohydrate digestion
Protein digestion
Fat digestion

8. Process of Digestion and Absorption
Large Intestine
Absorbs water
Absorbs salts (minerals)
Absorbs some vitamins
Stores waste for later elimination
Calcium from cheese has been absorbed. Fiber from tomatoes and lettuce remains.

9. Distribution and Use of Nutrients
Liver
regulates nutrient entry into blood
detoxifies blood
stores iron and fat-soluble vitamins
makes plasma proteins
stores and releases glucose
produces urea from amino acids
produces bile
destroys old red blood cells
helps regulate blood cholesterol

10. Applying Your Knowledge
Stomach
Mouth
Large Intestine
Small Intestine
Where are fats digested?
Where do proteins unfold?
Where does starch digestion begin?
Where is water absorbed?

11. Nutritional Recommendations
Macronutrients
Carbohydrate
Fat
Protein
Water
Micronutrients
Vitamins
Minerals
VEGETABLES
GRAINS
FRUITS
MEAT & BEANS
MILK
Use fats in small amounts

12. June 2011 Recommendations Balancing Calories
 Enjoy your food, but eat less. 
Avoid oversized portions.  
Foods to Increase 
Make half your plate fruits and vegetables. 
Make at least half your grains whole grains. 
Switch to fat-free or low-fat (1%) milk. 
 Foods to Reduce
 Compare sodium in foods like soup, bread, and frozen meals, and choose the foods with lower numbers. 
Drink water instead of sugary drinks.     

13. Carbohydrates: Dietary Recommendations
58% of calories from carbohydrates
No more than 10% of calories from simple, refined sugars
Emphasize
Complex Carbohydrates
Starch
Fiber (cellulose)
Naturally-occurring simple carbohydrates
Fructose from fruit
Lactose from milk

14. Fats: Dietary Recommendations
< 30% of calories from fats
< 10% of calories from saturated fats
Limit cholesterol to 300 mg/day
Avoid “trans” fatty acids in partially hydrogenated products
Emphasize
Unsaturated fatty acids from vegetables, fish, legumes, and nuts
Oils: mono- or polyunsaturated

15. Proteins: Dietary Recommendations
12% of calories from proteins
8 essential amino acids obtained from
Lean sources of animal protein
Complementary plant proteins
Beans + Grains
Beans + Seeds

16. Vitamins
Organic compounds used in metabolic reactions as coenzymes or antioxidants
Water Soluble: B vitamins, C
Fat Soluble: A, D, E, K
Adequate amounts come from a varied diet that includes vegetables and fruits
May prevent cancer and cardiovascular disease

17. Minerals Inorganic substances required by the body
Macrominerals needed in large amounts, eg. calcium
Microminerals needed in smaller amounts, eg. iron
May need to emphasize certain foods to obtain iron or calcium
May need to limit foods high in sodium

18. Applying Your Knowledge
Calcium
Vitamin C
Lipid
Carbohydrate
Protein
Which one is a mineral?
Which macronutrient should supply the greatest number of calories in the diet?
Which one may protect against cancer?

19. Reading a Nutrition Label
More info at

20. Calorie Percentage Calculations
Number of grams
Caloric value
Total calories
These should add to 100%.
12 x 9/250 = x 100 = 43.2%
3 x 9/250 = x 100 = 10.8%
31 x 4/250 = x 100 = 49.6%
5 x 4/250 = x 100 = 8.0%
5 x 4/250 = x 100 = 8.0%