1. DIGESTIVE SYSTEM
FUNCTION

2. 4 FUNCTIONS: 1. Physical breakdown of food into smaller pieces
2. Change food chemically by digestive juices into the end products of fat, carbs, and protein
3. Absorb nutrients into blood capillaries of the small intestine
4. Eliminate waste products of digestion

3. LOOK ON PG 392 FIGURE 18-15

4. DIGESTION TERMS Bolus Peristalsis Ptyalin Chyme Enzymes
Soft, pliable ball of semi-digested food
Peristalsis
Wavelike motions that move food along esophagus, stomach and intestines
Ptyalin
In saliva in mouth, converts starches to simple sugar
Chyme
Food which has undergone gastric digestion
Enzymes
Help in digestion
Chemical substances found in various digestive juices

5. DIGESTION in the STOMACH:
Gastric juices released
Stomach churns and mixes food and juice (chyme)
Small amounts chyme enter duodenum
Takes 2-4 hours for stomach to empty

6. DIGESTION in the SMALL INTESTINE:
Digestion completed, absorption occurs
Addition of enzymes from pancreas and liver (via gallbladder)

7. DIGESTION in the LARGE INTESTINE:
Large quantities of water absorbed back into bloodstream
Bacteria help break down undigested food
Gas formation (flatulence) from bacterial action
Feces
Undigested semi-solid waste
Defecation
Colon and rectal muscles contract, external anal sphincter under conscious control

8. MOUTH (Figure pg. 391)
Food enters digestive system through mouth
Broken down by teeth and mixed with saliva
Inside mouth covered with mucous membrane
Roof of mouth is hard palate
Uvula
Prevents food from going up nose when you swallow

9. TONGUE Attached to floor of mouth Helps in chewing and swallowing
Made of skeletal muscle
Taste buds on surface

10. SALIVARY GLANDS Three pairs Secrete saliva Parotid What are they?
Parotid: secretes ptyalin salivary amylase onto inner cheeks
Submandibular: secretes mucin and ptyalin at base of tongue
Sublingual: secretes mucous (no ptyalin) and found on either sides of tongue
Smallest of the three
Secrete saliva
Parotid
Largest salivary glands, become inflamed during mumps

11. TEETH Gingiva – gums that support and protect teeth
Mastication – chewing
Deciduous – baby teeth
How many?
Adult teeth

12. STOMACH Cardiac sphincter Pyloric sphincter Rugae
Circular layer of muscle
Controls passage of food into stomach
Pyloric sphincter
Regulates entrance of food into duodenum
Rugae
Mucous coat lining
Folds when stomach empty
Muscular coat contracts (peristalsis) to push food into small intestine

13. SMALL INTESTINE Three sections: Absorption Read “Did you know?”
What are they? Look on pg. 385
Absorption
Digested food (nutrients) pass into bloodstream and on to body cells
Undigestable passes on to large intestine
Read “Did you know?”

14. SMALL INTESTINE continued
END PRODUCTS OF DIGESTION:
Carbohydrates are converted to simple sugars such as glucose
Proteins are broken down into amino acids
Fats are changed into fatty acids and glycerol

15. PANCREAS and GALLBLADDER
Exocrine function – secretes digestive enzymes
Also has endocrine function
Gallbladder
Stores bile
When fatty foods digested, bile released by gallbladder

16. LIVER Manufactures bile
Produces and stores glucose in the form of glycogen
Detoxifies alcohol, drugs and other harmful substances
Manufactures blood proteins
Stores vitamin A, D and B complex

17. LARGE INTESTINE Water absorption Bacterial action Fecal formation
Gas formation
Defecation
Look on pg. 393 and WRITE DOWN a few notes on each