1. DIGESTION
ABSORPTION

2. GI TRACT

3. ANATOMY OF GI TRACT

4. MOUTH Chewing  surface area of food Mixes fluid (saliva) in with food
Taste
Ease of swallowing
CHO digestion (amylase) NO digestion of fibers and sugars
Epiglottis prevents choking
cartilage in throat to close off
windpipe

5. NORMAL SWALLOW STAGES
ORAL PHASE- food bolus moves to back of mouth (voluntary)
PHARYNGEAL PHASE – triggering of the swallow (reflexive stage)
ESOPHAGEAL PHASE – actual swallow (reflexive)

6. DYSPHAGIA - SYMPTOMS ORAL PHASE drooling pocketing facial droop
inadequately chewed foods
food falling out of the mouth
excessive tongue movement

7. DYSPHAGIA CONT’D PHARYNGEAL PHASE “Gurgling” voice food getting stuck
nasal regurgitation
delayed swallowing reflex
coughing while eating or drinking

8. TEST OF SALIVARY SECRETIONS

9. GI TRACT BOLUS – mouthful of swallowed food PERISTALSIS –
powerful rhythmic waves
propels food along
circular and longitudinal muscles
speed varies

10. PERISTALISIS

11. ESOPHAGUS TO STOMACH Esophagus  diaphragm
Cardiac sphincter – 1 way valve between esophagus and stomach
Stomach
CHO digestion stops in the stomach
Saliva – is a protein and is digested
Problems:
Hiatal hernia
GERD
Heartburn – acidic stomach contents into esophagus

12. HERNIA

13. GERD

14. STOMACH
Muscular, elastic, saclike, thickest walls, strongest muscles in GI tract
Parietal cells on wall release Gastrin
Gastrin stimulates release of HCl ( pH)
HCl denatures protein
HCl activates pepsinogen (enzyme)  pepsin
Pepsin  large proteins smaller amino acids
Digestion of protein – little else

15. STOMACH Churning circular longitudinal diagonal
Food mixed with water ~ 2 liters per day
Chyme (“kime”) – very acidic
semiliquid mass of partly digested food and fluid
Stomach protected by mucus membrane-from goblet cells

16. STOMACH

17. pH VALUES

18. STOMACH SURGERY

19. PYLORIC SPHINCTER Circular muscle-1 way valve Opens 3 times/minute
Waits to re-open until chyme neutralized
Chyme released in small squirts
Neutralized by bicarbonate from pancreas

21. SMALL INTESTINE Three segments Duodenum Jejunum Ileum
Digestion completed for CHO, PRO, Fat
Pancreatic enzymes-specific to need
proteases, lipases, carbohydrases
Intestinal enzymes
Bile (emulsifier)-livergallbladder

22. SMALL INTESTINE - ABSORPTION
Microvilli- fingerlike projections
Crypts – secrete digestive enzymes
Specific areas for absorption of specific nutrients- absorption of most nutrients
Absorbed into lymph or blood
BLOOD – liver via portal vein
LYMPH – bloodstream via thoracic duct and subclavian vein

23. SMALL INTESTINAL VILLI

24. ABSORPTION OF NUTRIENTS
Diffusion – freely crosses cell membrane
Facilitated diffusion – specific carriers required but no energy
Active transport – requires carriers and energy

25. ILEOCECAL VALVE
One way valve between small and large intestine

26. ABSORPTION SITES

27. LARGE INTESTINE Colon – three segments Ascending colon
Transverse colon
Descending colon
Normal bacterial action
Fiber  kcals
Vitamin K + others?
Absorption
water and some minerals

28. LARGE INTESTINE FUNCTION
Food in large intestine hours
Water reabsorbed – if not diarrhea
Home for bacteria
Feces formed here
Few minerals absorbed

29. STOMAS

30. CROSS-SECTION

31. THE END Rectum – semisolid waste (feces)
Defecation – elimination of waste from body – “moving of bowels”
Anus – terminal sphincter, opens to outside of body – YOU control this valve