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THE DIGESTIVE SYSTEM II

THE DIGESTIVE SYSTEM II. D. C. Mikulecky Faculty Mentoring Program Virginia Commonwealth University. PANCREATIC AND BILLIARY SECRETIONS. THE PANCREAS IS BOTH ENDOCRINE AND EXOCRINE THE EXOCRINE PANCREAS SECRETES DIGESTIVE ENZYMES AND AN AQUEOUS ALKALINE FLUID

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THE DIGESTIVE SYSTEM II

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  1. THE DIGESTIVE SYSTEM II D. C. Mikulecky Faculty Mentoring Program Virginia Commonwealth University

  2. PANCREATIC AND BILLIARY SECRETIONS • THE PANCREAS IS BOTH ENDOCRINE AND EXOCRINE • THE EXOCRINE PANCREAS SECRETES DIGESTIVE ENZYMES AND AN AQUEOUS ALKALINE FLUID • PANCREATIC SECRETION IS HORMONALLY REGULATED • PANCREATIC SECRETIONS REACH THE SMALL INTESTINE VIA THE COMMON BILE DUCT

  3. THE EXOCRINE PANCREAS SECRETES DIGESTIVE ENZYMES • PROTEOLYTIC ENZYMES • PANCREATIC AMYLASE • PANCREATIC LIPASE

  4. HORMONAL CONTROL OF PANCREATIC SECRETION • ACID IN DUODENAL LUMEN >SECRETIN: STIMULATES PANCREATIC DUCT CELLS TO PRODUCE SIGNIFICANT QUANTITES OF AQUEOUS ALKALINE SECRETION • FAT AND PROTEIN IN DUODENAL LUMEN>CHOLECYSTOKININ (CCK):STIMULATES PANCREATIC ACINAR CELLS TO SECRETE DIGESTIVE ENZYMES

  5. FUNCTIONS OF THE LIVER • METABILIC PROCESSING OF ABSORBED FOOD • DETOXIFICATION2 • SYNTHESIS OF PLASMA PROTEINS • STORAGE OF GLYCOGEN AND FAT, ETC. • REMOVAL OF BACTERIA AND WORN-OUT RBC • EXCRETION OF CHOLESTEROL AND BILIRUBIN

  6. BILE SECRETION, STORAGE, AND CIRCULATION • SECRETED BY THE LIVER • RECYCLED THROUGH ENTEROHEPATIC CIRCULATION • STORED IN GALL BLADDER

  7. LIVER BLOOD FLOW INFERIOR VENA CAVA AORTA HEART HEPATIC VEIN HEPATIC ARTERY LIVER HEPATIC PORTAL VEIN ARTERIES TO DIGESTIVE TRACT STOMACH AND SMALL INTESTINE

  8. BILE SALT CIRCULATION LIVER GALL BLADDER SPHINCTER OF ODDI DUODENUM

  9. S.I. MOTILITY • SEGMENTATION CONTRACTIONS • PACEMAKER CELLS • MIXING AND PROPULSION

  10. SEGMENTATION CONTRACTIONS • INITIATED BY PACEMAKER CELLS • MIXING ACTION • MOVES CHYME DOWNWARD • ILEOCECAL VALVE

  11. S.I. SECRETIONS • MANLY MUCOUS • NO DIGESTIVE ENZYMES

  12. DIGESTION • MAINLY IN THE SMALL INTESTINE • PANCREATIC ENZYMES • BRUSH BORDER ENZYMES

  13. ABSORPTION • LARGE SURFACE AREA • ACTIVE SODIUM TRANSPORT • FLUID AND ELECTROLYTES • SUGARS AND AA BY SECONDARY ACTIVE TRANSPORT • FAT • VITAMINS AND MINERALS

  14. LARGE SURFACE AREA • LONG TUBE • CIRCULAR FOLDS • VILLI • MICROVILLI • SIZE OF TENIS COURT

  15. FLUID AND ELECTROLYTES • SODIUM IS ACTIVELY TRANSPORTED ALONG CELL’S BASOLATERAL MEMBRANE • CHLORIDE FOLLOWS FOR ELECTRONEUTRALITY • WATER FOLLOWS FOR OSMOTIC BALANCE • POTASSIUM AND OTHER ELECTROLYTES ARE MAINLY ABSORBED BY PASSIVE DIFFUSION

  16. Absorption is a Function of the Epithelial Cells Making up the Intestinal Wall Plasma Lumen Cells

  17. Sodium Absorption PUMP: Na/K ATPase Plasma Sodium Lumen Cells Potassium Chloride Water

  18. AVERAGE DAILY INTAKE OF IRON (NORTH AMERICA AND EUROPE) • BETWEEN 10 AND 30 mg • ABOUT 5 TO 7 mg PER 1000 CALORIES • IF ON A 1000 TO 1500 CALORIE DIET, ONLY 6-9 mg • INFLUENCED BY COOKING UTENSILS • DEPENDS ON BEVERAGE CONSUMPTION

  19. THE LARGE INTESTINE • PRIMARILY A DRYING AND STORAGE ORGAN • HAUSTRAL CONTRACTIONS • MASS MOVEMENTS • PROTECTIVE SECRETIONS • FORMATION OF FECES

  20. THE DEFICATION REFLEX • DISTENTION OF RECTUM STIMULATES • INTERNAL ANAL SPHINCTER (SMOOTH MUSCLE) RELAXES • EXTERNAL ANAL SPHINCTER (SKELETAL MUSCLE) UNDER VOLUNTARY CONTROL

  21. GASTROINTESTINAL HORMONES • GASTRIN • SECRETIN • CHOLECYSTOKININ

  22. GASTRIN • ENDOCRINE CELLS IN PYLORIC STOMACH • STIMULATED BY PROTEIN IN STOMACH • STIMULATES SECRETION BY PARIETAL AND CHIEF CELLS • STIMULATES ILEAL MOTILITY • RELAXES ILEOCECAL SPHINCTER • INDUCES COLONIC MASS MOVEMENTS

  23. SECRETIN • ENDOCRINE CELLS IN DUODENAL MUCOSA • ACID IN DUODENAL LUMEN • INHIBITS GASTRIC EMPTYING • INHIBITS GASTRIC SECRETION • STIMULATES AQUEOUS BICARBONATE SECRETION BY PANCREAS • STIMULATES BICARBONATE RICH BILE SECRETION BYLIVER

  24. CHOLECYSTOKININ • ENDOCRINE CELLS IN DUODENAL MUCOSA • FAT AND PROTEIN IN DUODENAL LUMEN • INHIBITS GASTRIC EMPTYING • INHIBITS GASTRIC SECRETION • CAUSES GALL BLADDER CONTRACTION • CAUSES RELAXATION OF THE SPHINCTER OF ODDI • CONTRIBUTES TO SATIETY

  25. TOTAL BODY IRON IN HUMANS • WEIGHT • SEX • SIZE OF STORAGE COMPARTMENT • HEMOGLOBIN CONCENTRATION • HISTORY

  26. ABSORPTION OF IRON FROM FOODS

  27. SOME DISEASES LINKED WITH DIET • CANCER • HEART DISEASE • HIGH BLOOD PRESSURE • OBESITY • DIVERTICULITIS

  28. FOOD INGREDIENTS AND DISEASE • REFINED SUGAR • FAT • SALT • LOW IN FIBER

  29. CANCER AND DIET: PHYTOCHEMICALS • FOUND ONLY IN PLANTS • IMMUNE FUNCTION • HORMONE BALANCE • DETOXIFICATION

  30. CANCER AND DIET N.R.C.RECOMMENDATIONS • EAT LESS FAT (30% OR LESS 0F TOTAL CALORIES) • EAT FRUITS, VEGITABLES, AND WHOLE-GRAIN CEREAL FOODS EVERY DAY (ESPECIALLY THOSE HIGH IN VITAMINS A AND C) • AVOID HIGH DOSE SUPPLIMENTS OF VITAMINS OR OTHER NUTRIENTS • ALCOHOL ONLY IN MODERATION

  31. PROTEIN SOURCES-EXCEPTIONS • SOYBEANS • QUINONA • SPINACH • HAVE THE SAME QUALITY AS MILK

  32. INCOMPLETE PROTEINS NEEDED TO MEET REQUIREMENTS • 2 2/3 CUPS COOKED WHEAT • 3 CUPS COOKED RICE • 5 3/4 SLICES BASIC BREAD • 3 CUPS DICED POTATOES • 1/3 CUP SOY SPREAD • 1/2 CUP WHEAT GERM • 2 3/4 CUPS RICE WITH 1/3 CUP COOKED PEAS

  33. SOME WAYS TO CUT DOWN ON FAT • EAT MORE VEGETARIAN MEALS • EAT MORE FRESH FRUIT OR YOGURT INSTEAD OF DESSERTS • USE YOGURT AS DRESSING INSTEAD OF OIL • USE FRESH HERBS INSTEAD OF BUTTER (AND INSTEAD OF SALT)

  34. FIBER • ROUGHLY SPEAKING, EVERYTHING IN PLANT FOODS OUR DIGESTIVE ENZYMES CAN NOT BREAK DOWN • NURTURES AEROBIC BACTERIA IN GUT • SOLUABLE FIBER REDUCES INSULIN NEED IN DIABETICS • CHELATORS-INCREASE NEED FOR MINERALS

  35. TYPES OF FIBER • PECTINS: IN CELL WALL OF FRUITS, BIND BILE SALTS • GUMS: STICKY SUBSTANCES EXUDED BY PLANTS, LOWER CHOLESTEROL UPTAKE AND SLOW SUGAR ABSORPTION • CELLULOSE: PLANT CELL WALLS, BULK AND TOXIN ELIMINATION • HEMICELLULOSES: PLANT CELL WALLS, BULK • LIGNIN: ROOT VEGETABLES, BULK

  36. EFFECT ON MICROFLORA • LOWER TOTAL ANAEROBIC, IN PARTICULAR, CLOSTRIDIUM • DIET CAN ALTER THE METABOLIC ACTIVITY OF THE FLORA • MEAT AND UNREFINED SUGAR INCREASES UNWANTED BACTERIA • VEGETARIAN DIET LOWERS RISKS OF BOWEL CANCER

  37. RECOMMENDED FIBER INTAKE • 20 - 25 g/day WITH AN UPPER LIMIT OF 35 g/day • FAMILY HISTORY OF DIET-IMPLICATED CANCER 35-40 g/day • DIABETICS UP TO 50 g/day

  38. SOURCES OF FIBER • LEGUMES (ALSO PROTEIN SOURCE) • FRUITS AND VEGETABLES • WHOLE GRAIN CEREALS AND FLOURS

  39. SOLUABLE SOME HEMICELLULOSE PECTIN GUM MUCILAGES INSOLUABLE LIGNIN CELLULOSE SOME HEMICELLULOSE SOLUABLE AND INSOLUABLE DIETARY FIBER

  40. CHELATORS LOWER MINERAL ABSORPTION • PHYTATES • OXALATES

  41. SUPPLIMENTS FROM PLANTS • ECHINACEA: IMMUNE BOOSTING AND ANTIBIOTIC • PSYLLIUM SEEDS: SOURCE OF FIBER • CHAMOMILE: MILD SEDATIVE • ALOE VERA: PROMOTES HEALING • SAW PALMETTO EXTRACT: PROSTATE PROBLEMS • GREEN TEA: ANTI CANCER , ANTIOXIDENT • GARLIC: ANTIBACTERIAL, ANTIVIRAL, LOWERS CHOLESTEROL

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