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DIGESTIVE PHYSIOLOGY PHYSIOLOGICAL PROCESSES • • • • MECHANICAL PROCESSES SECRETION CHEMICAL DIGESTION ABSORPTION MECHANICAL PROCESSES MOVEMENT PATTERNS SEGMENTATION • STATIONARY MUSCULAR CONTRACTIONS • DIVIDES GI TRACT INTO CONSTRICTED OR UNCONSTRICTED SECTIONS PERISTALSIS • WAVE LIKE CONTRACTION • FORCES MATERIALS TO MOVE BEFORE IT • NORMALLY MOVES TOWARD ANUS • PROBABLY DUE TO INTRINSIC NERVE PLEXUS CHEWING • MASTICATION • FORMS BOLUS • REDUCES FOOD INTO SMALLER PIECES THAT ARE EASIER TO DIGEST SWALLOWING • MOVES BOLUS FROM MOUTH TO STOMACH • INITIATED BY TONGUE ON ROOF OF MOUTH • PRESSURE RECEPTORS AT OPENING OF PHARYNX INITIATE SWALLOWING REFLEX SWALLOWING REFLEX • PHARYGEAL CONSTRICTOR MUSCLES • PERISTALTIC CONTRACTION UPPER ESOPHAGEAL SPHINCTER • KEEPS ESOPHAGUS CLOSED EPIGLOTTIS • WITH VOCAL CORDS KEEP FOOD FROM GOING INTO TRACHEA • COUGHING REMOVES FOOD THAT DOES GET INTO TRACHEA MOVEMENT ALONG THE ESOPHAGUS • PERISTALTIC CONTRACTIONS • TUNICA MUSCULARIS LOWER ESOPHAGEAL SPHINCTER • 2-5 CM ABOVE CARDIAC ORIFICE • KEEPS OPENING TO STOMACH CLOSED • FOOD GENERALLY TAKES ABOUT 5 10 SECONDS TO REACH STOMACH GASTRIC MOTILITY MECHANICAL ACTIVITIES OF STOMACH • STORING FOOD • MIXING FOOD WITH GASTRIC SECRETIONS • MOVEMENT OF FOOD INTO DUODENUM STOMACH VOLUME • ABOUT 50 ML NORMALLY • CAN EXPAND TO TO 1000-1500ML • WILL NOT HAVE AN INCREASE IN PRESSURE • DUE TO SMOOTH MUSCLE ABILITY TO LENGTHEN WITHOUT INCREASING TENSION • ALSO DUE TO RECEPTIVE RELAXATION CHYME • SEMIFLUID MIXTURE OF FOOD AND GASTRIC SECRETIONS PYLORIC SPHINCTER • USUALLY PARTIALLY OPEN • OFFERS ONLY LIMITED RESISTANCE STOMACH MUSCLE CONTRACTIONS • BEGIN IN BODY • MOVE TOWARD PYLORIC SPHINCTER • INCREASE IN STRENGTH AND SPEED IN LOWER REGIONS • FORCES CHYME OUT OF STOMACH INTO DUODENUM • MATERIAL LEFT OVER REBOUNDS BACK INTO STOMACH PACESETTER CELLS • SLOW WAVE POTENTIALS • GIVES SMOOTH MUSCLE A BASIC ELECTICAL RHYTHM • THREE CYCLES PER MINUTE CYCLES FACTORS THAT INFLUENCE MEMBRANE POTENTIALS • MECHANICAL • HORMONAL • NEURAL MECHANICAL FACTORS • VOLUME OF STOMACH • MECHANORECEPTORS INTIATE REFLEXES TO INCREASE GASTRIC MOTILITY RELAXATION OF PYLORIC SPHINCTER PROMOTION OF GASTRIC EMPTYING • BOTH LONG AND SHORT REFLEXES INVOLVED SHORT REFLEXES • NEURAL SIGNALS ORIGINATE FROM WALL OF DIGESTIVE TRACT • TRANSMITTED BY INTRINSIC NERVE PLEXUSES TO EFFECTOR CELLS • ALL ELEMENTS ARE LOCATED IN DIGESTIVE TRACT WALL LONG REFLEXES • AFFERENT IMPULSES TO BRAIN CENTERS • EFFERENT IMPULSE TO INTRINSIC PLEXUSES AND EFFECTOR CELLS OF DIGESTIVE SYSTEM HORMONAL FACTORS • GASTRIN EFFECT OF VOLUME AND COMPOSITION OF CHYME ENTERING DUODENUM • EXERTS MAJOR EFFECT ON GASTRIC MOTILITY • EXERTS MAJOR EFFECT ON GASTRIC EMPTYING • EXERTS BOTH HORMONAL AND NEURAL CONTROL ENTEROGASTRIC REFLEX • WHEN DUODENUM FILLS WITH CHYME • DISTENSION OF WALL • INHIBITS GASTRIC MOTILITY • INCREASES CONTRACTION OF PYLORIC SPHINCTER ENTEROGASTERONES • COLLECTION OF HORMONES • RELEASED IN RESPONSE TO ACID CHYME • PRESENCE OF FAT • PRESENCE OF CERTAIN AMINO ACIDS • INHIBIT GASTRIC MOTILITY AND SLOW GASTRIC EMPTYING ENTEROGASTERONES • SECRETIN • MAYBE CCK AND GIP NET EFFECT • TO SLOW MOVEMENT OF CHYME UNTIL SMALL INTESTINE HAS PROCESSED WHAT IT ALREADY HAS SMALL INTESTINE MOTILTY SEGMENTATION • MAJOR MOVEMENT • MOST COMMON MOVEMENT DURING MEAL • QUITE ACTIVE JUST AFTER MEAL • LITTLE OCCURS BETWEEN MEALS • MIXES CHYME WITH DIGESTIVE JUICES • INCREASES EXPOSURE TO MUCOSA SMOOTH MUSCLE • HAS BASIC ELECTRICAL RHYTHM • DETERMINES FREQUENCY OF SEGMENTATION CONTRACTIONS • RATE VARIES THROUGHOUT SMALL INTESTINE • GREATEST SEGMENTATION IN UPPR PART • LEAST IN LOWER PART FACTORS THAT AFFECT SEGMENTATION • MECHANICAL • NEURAL • HORMONAL MIGRATING MOTILITY COMPLEX • SERIES OF WEAK PERISTALTIC CONTRACTIONS • BEGINS AT DUODENUM • NEW WAVES CONTINUE THROUGHOUT SMALL INTESTINE • 100-150 MINUTES ILEOCECAL SPHINCTER • CONTROLS MOVEMENT OF MATERIALS INTO CECUM • MATERIAL IN CECUM INTIATES INTRINSIC NERVE PLEXUS TO STIMULATE SPHINCTER • USUALLY MILDLY CONSTRICTED • ALLOWS TIME FOR ABSORPTION GASTROILEAL COMPLEX • REFLEX THAT INCREASES ILEAL CONTACTION • OCCURS WHEN FOOD ENTERS STOMACH GASTRIN • INCREASE MOTILITY IN ILEUM • RELAXES ILEOCECAL SPHINCTER • INCREASES MOVEMENT INTO CECUM • ALLOWS ROOM IN STOMACH FOR MORE FOOD ILEOCECAL VALVE • FOLDS OF TISSUE • PROTECTS OPENING OF ILEUM INTO CECUM • PREVENTS BACK FLOW LARGE INTESTINE MOTILITY • SLUGGISH • 18-24 HOURS FOR MOVEMENT THROUGH SEGMENTATION • LOWER RATE THAN IN SMALL INTESTINE • CALLED HAUSTRAL CONTACTIONS • MAY OCCUR EVERY THIRTY MINUTES OR SO MASS MOVEMENTS • OCCUR THREE OR FOUR TIMES PER DAY • LARGE SEGMENTS OF COLON EXPERIENCE STRONG CONTRACTIONS • MOVE CONTENTS FOR LONG STRETCHES • OFTEN OCCUR AFTER MEALS FACTORS THAT MAY INTITIATE MASS MOVEMENTS • DUODENUM MAY INTITIATE DUODENOCOLIC REFLEX • STOMACH MAY INTITIATE GASTROCOLIC REFLEX • NET EFFECT IS TO MAKE ROOM FOR MORE FOOD DEFECATION REFLEX • MOVES MATERIAL OUT OF LOWER COLON AND RECTUM • TRANSMITTED BY INTRINSIC PLEXUS • REINFORCED BY INPUT FROM SACRAL REGION EFFECTS OF DEFECATION REFLEX • SIGMOID COLON AND RECTUM CONTRACT • INTERNAL ANAL SPHINCTER RELAXES • FECES PROPELLED INTO ANUS • EXTERNAL ANAL SPHINCTER DETERMINES WHETHER IT WILL LEAVE ACTIVITIES THAT ASSIST THE DEFECATION REFLEX • DEEP INSPIRATION • HOLDING BREATH • CONTRACTING ABDOMINAL MUSCLES • THESE ACTIVITIES RAISE ABDOMINAL PRESSURE SECRETORY ACTIVITIES OF GI TRACT ORAL REGION • • • • PAROTID GLAND SUBLINGUAL GLAND SUBMANDIBULAR GLAND BUCCAL GLAND TYPES OF SALIVA • MUCOUS SECRETION • SEROUS SECRETION PAROTID GLAND • SEROUS SECRETIONS SUBMANDIBULAR GLAND • SEROUS BUCCAL AND SUBLINGUAL GLANDS • PRIMARILY MUCOUS MUCOUS SECRETION • CONTAINS MUCIN MAJOR PROTEINS OF SALIVA MIX WITH WATER TO FORM MUCOUS • HIGHLY VISCOUS • LUBRICATES FOOD • RESPONSIBLE FOR HOLDING BOLUS TOGETHER MUCINS • MAJOR PROTEINS OF SALIVA • ATTACHED TO LARGE POLYSACCHARIDES • MIX WITH WATER TO FORM MUCUS IMPORTANCE OF SALIVARY AMYLASE • SPLITS STARCH MOLECULES INTO SMALLER UNITS • OPTIMAL PH 6.9 • RANGE 4 TO 11 • BEGINS DIGESTION OF CARBOHYDRATES • CONTINUES IN STOMACH UNTIL ACIDS INACTIVATE SALIVA COMPOSITION • VARIABLE BASED ON GLAND SECRETING AND STIMULUS THAT CAUSES ITS SECRETION • 97-99.5 % WATER • PH FROM 6.--7.0 • KALLIKREIN • BLOOD GROUP SUBSTANCES ELECTROLYTES IN SALIVA • • • • SODIUM POTASSIUM CHLORIDE BICARBONATE FUNCTIONS OF SALIVA • • • • • • LUBRICATION DIGESTION BOLUS FORMATION DISSOLVES FOOD SO WE CAN TASTE AIDS IN SPEECH BACTERIOSTATIC CONTROL OF SALIVARY SECRETIONS • NEURAL CONTROL • SALVATORY NUCLEI IN PONSMEDULLA RECEIVE INPUT FROM MAOUTH AND PHARYNX • AUTONOMIC NERVOUS SYSTEM CARRIES INPUT TO SALIVARY GLANDS FACTORS THAT ENHANCE SECRETION • • • • SIGHT OF FOOD THOUGHT OF FOOD ODOR OF FOOD PRESENCE OF IRRITATING FOODS IN STOMACH OR SMALL INTESTINE • CHEWING FACTORS THAT INHIBIT SECRETION • • • • INTENSE MENTAL EFFORT DEHYDRATION FEAR ANXIETY GASTRIC SECRETIONS • MUCUS • HYDROCHLORIC ACID • PEPSINOGEN MUCUS • • • • • • VISCOUS ALKALINE FORMS A LAYER 1-1.5 MM THICK LUBICATES WALL PROTECTS GASTRIC MUCOSA IRRITATED MUCOSA SECRETES LOTS OF MUCUS GLANDS THAT SECRETE MUCUS • CARDIAC GLANDS • PYLORIC GLANDS • GASTRIC GLANDS IN FUNDUS AND BODY WILL ALSO SECRETE WITH OTHER PRODUCTS HYDROCHLORIC ACID • PARIETAL CELLS OF GASTRIC GLANDS • DISSOCIATES INTO H+ AND CL- IONS • FACILITATES PROTEIN DIGESTION • KILLS MANY BACTERIA • SECRETORY PRODUCT AT PH OF 1.8 • ACTUAL PH OF STOMACH WILL VARY THEORIES OF HCL PRODUCTION • HYDROGEN IONS ARE DISSOCIATED FROM WATER MOLECULES • ACTIVELY TRANSPORTED FROM INTERIOR OF PARIETAL CELLS TO STOMACH LUMEN • LEAVES BEHIND HYDROXIDE ION • CARBON DIOXIDE DIFFUSES INTO CELL FROM PLASMA • WITH CARBON DIOXIDE FROM METABOLISM COMBINES WITH WATER TO FORM CARBONIC ACID • CARBONIC ANHYDRASE CATALYZES • HYDROGEN AND HYDROXIDE IONS JOIN TO FORM WATER • ACTIVE TRANSPORT REMOVES BICARONATE IONS INTO PLASMA IN EXCHANGE FOR CHLORIDE IONS • CHLORIDE IONS LEAVE CELL AND ENTER LUMEN OF STOMACH EFFECT ON PLASMA pH • BICARBONATE CAUSES PH OF VENOUS BLOOD FROM STOMACH TO BE HIGHER THAN BLOOD FLOWING TO THE STOMACH PEPSINOGEN • ZYMOGENIC OR CHIEF CELLS • PRECURSOR TO PEPSIN • ACIDIC ENVIRONMENT CAUSES CONVERSION • PEPSIN CAN ALSO CONVERT OTHER PEPSINOGENS PEPSIN • WORKS BEST IN ACID ENVIRONMENT • DIGEST PROTEINS BY BREAKING PEPTIDE BONDS INVOLVING: TRYTOPHAN, PHENYLALANINE, AND TYROSINE • PRODUCES SMALLER PEPTIDE CHAINS MUCUS PRODUCTION AND THE PROTECTION OF THE STOMACH • • • • MUCUS COMBINED WITH EPITHELIA TIGHT JUNCTIONS HYDROPHOBIC LAYER SECRETION OF PESPSINOGEN CONTROL OF GASTRIC SECRETIONS • CEPHALIC PHASE • GASTRIC PHASE • INTESTINAL PHASE CEPHALIC PHASE • • • • • SIGHT SMELL TASTE DUE TO SENSORY INPUT TO CNS VAGUS CARRIES INPUT FROM CNS TO STOMACH • CONDITIONED REFLEX GASTRIC PHASE • SIGNALS ORIGINATE IN STOMACH • DISTENSION OF STOMACH • INCREASES AMOUNT OF PEPSIN AND ACIDITY CONTROL OF GASTRIC PHASE • SHORT REFLEXES • LONG REFLEXES FACTORS THAT CAUSE THE PRODUCTION OF GASTRIN • DISTENSION OF PYLORIC REGION CAUSES LOCAL REFLEXES • SECRETAGOGUES CAFFEINE PARTIALLY DIGESTED PROTEIN FACTORS THAT INHIBIT GASTRIN RELEASE • HIGH CONCENTRATIONS OF HYDROGEN IONS IN STOMACH • PH OF TWO BLOCKS GASTRIN PRODUCTION INTESTINAL PHASE • CAUSED BY SIGNALS FROM SMALL INTESTINE • WEAK EXCITATORY COMPONENT • STRONGER INHIBITORY COMPONENT EXCITATORY COMPONENT • CAN BE SEEN WHEN CHYME ENTERS DUODENUM • PROBABLY DUE TO INTESTINAL GASTRIN FROM DUODENAL MUCOSA • OTHER HORMONES ARE INVOLVED INHIBITORY COMPONENT • NEURAL • HORMONAL FACTORS INVOLVED • DISTENSION OF DUODENUM • EXCESSIVE ACIDITY OF CHYME • HYPER OR HYPOTONICITY OF CHYME • INTITIATES ENTEROGASTRIC REFLEX • SHORT AND LONG REFLEXES ENTEROGASTERONES • ACIDITY OF CHYME • PRESENCE OF SOME FATS OR AMINO ACIDS • ARE INHIBITORY SECRETIONS FOUND IN THE SMALL INTESTINE • • • • MUCUS INTESTINAL JUICE PANCREATIC JUICE BILE MUCUS • PROTECTIVE COATING FACTORS THAT STIMULATE SECRETION • • • • TACTILE STIMULATION OF MUCOSA IRRITATION OF MUCOSA VAGAL STIMULATION SECRETIN AND OTHER INTESTINAL HORMONES SITES OF SECRETION • GOLBET CELLS • DUODENAL CELLS • INTESTINAL GLANDS CONTROL OF SECRETION • MOST LIKELY DUE TO LOCAL NERVE REFLEXES INTESTINAL JUICE • LOCATED THROUGHOUT SMALL INTESTINE • PH OF 6.5 TO 7.5 • ISOTONIC TO PLASMA FACTORS THAT AFFECT SECRETION • LOCAL REFLEXES INTIATED BY INTESTINAL MUCOSA • SECRETIN • CCK SECRETION • PRODUCED BY EPITHELIAL CELLS • ENZYMES ARE ASSOCIATED WITH CELL MEMBRANES NOT IN LUMEN • INCLUDES: DISSACHRIDASES AND PEPTIDASES PANCREATIC JUICE • • • • • EXOCRINE PRODUCT AQUEOUS ISOTONIC HIGH BICARBONATE ION LEVEL PH 8.0 ENZYMES • • • • • VARIOUS CARBOHYDRATE ENZYME PROTEASES LIPIDASES RIBONUCLEASES DOXYRIBONUCLEASES CONTROL OF SECRETION • HORMONAL • NEURAL HORMONAL • SECRETIN • CCK SECRETIN • RELEASED IN RESPONSE TO ACID IN DUODENUM • RELEASE OF WATERY BICARBONATE SOLUTIONS CCK • PRESENCE OF CERTAIN AMINO ACIDS AND FATTY ACIDS IN DUODENUM • RELEASE OF DIGESTIVE ENZYMES NEURAL • VAGUS • EFFECTS MAINLY ENZYMATIC SECRETION • OCCURS MAINLY IN CEPHALIC AND GASTRIC PHASES BILE • PRODUCED BY LIVER • 600-1000 ml PER DAY • TRAVELS TO SMALL INTESTINE BY DUCTS • CAN BE STORED IN GALL BLADDER COMPONENTS OF BILE • AQUEOUS SOLUTION • SODIUM • BICARBONATES • CHOLIC AND CHENODEOXYCHL IC ACIDS • • • • BILIRUBIN CHOLESTEROL NEUTRAL FATS LECITHIN FATE OF BILE • 94% REABOSRBED IN ILEUM • RETURNED TO LIVER BY ENTEROHEPATIC CIRCULATION CONTOL OF BILE SECRETION • CHEMICAL • HORMONAL • NEURAL CHEMICAL • BILE SALTS IN PLASMA CAUSE SECRETION OF MORE BILE SALTS HORMONAL • SECRETIN NEURAL • PARASYMPATHETIC INNERVATION BY VAGUS BILE STORAGE • GALLBLADDER • CAN STORE 40 TO 70 ML • REABSORBS WATER AND ELECTROLYTES • CONCENTRATION OF BILE SALTS AND PIGMENTS CAN INCREASE 5TO TEN TIMES ROLE OF GALLBLADDER IN DIGESTION • GALLBLADDER CONTRACTION RELEASES BILE INTO DUODENUM • PRIMARILY CAUSED BY CCK • PARASYMPATHETIC INNERVATION CAN CAUSE WEAK CONTRACTIONS SECRETIONS OF THE LARGE INTESTINE • MUCUS • MUCUS • AND MORE MUCUS CONTROL OF MUCUS SECRETIONS • DIRECT TACTILE STIMLATION • INTRINSIC REFLEXIS • EXTRINSIC REFLEXES DIGESTIVE PROCESSES DIGESTION • BREAKDOWN LARGE MOLECULES INTO SMALLER ONES • WORK BY HYDROLYSIS • SMALL INTESTINE DOES MOST ABSORPTION • • • • • PRODUCTS OF DIGESTION VITAMINS MINERALS WATER SMALL INTESTINE DOES MOST DIGESTION OF COMMON NUTRIENTS CARBOHYDRATES • STARCH • SUCROSE • LACTOSE STARCHES • AMYLASES IN SALIVA • AMYLASES IN PANCREATIC JUICE • STARCH IS BROKEN INTO ALPHADEXTRIN MALTOTRIOSE AND MALTOSE SUCROSE • GLUCOSE • FRUCTOSE LACTOSE • GLUCOSE • GALACTOSE ENZYMES INVOVED • • • • • LOCATED ON MICROVILLI ALPHA DEXTINASE MALTASE SUCRASE LACTASE ABSORPTION OF SUGARS • PRIMARILY IN DUODENUM AND UPPER JEJUNUM • GLUCOSE AND GALACTOSE--ACTIVE TRANSPORT • FRUCTOSE--FACILITATED DIFFUSION PROTEINS ENZYMES THAT DIGEST PROTEINS • TRYPSIN • CHYMOTRYPSIN • CARBOXYPEPTIDASE TRYPSIN • BREAKS BONDS BETWEEN LYSINE AND ARGININE CHYMOTRYPSIN • BREAKS BONDS BETWEEN TYROSINE AND PHENYLALANINE CARBOXYPEPTIDASE • REMOVES CARBOXYL GROUP FROM END OF AMINO ACID ENZYMES OF MICROVILLI • • • • CONTINUE PROCESS AMINOPEPTIDASES TETRAPEPTIDASES TRIPEPTIDASES SITES OF PROTEIN DIGESTION • BEGINS IN STOMACH • MOST OCCURS IN SMALL INTESTINE • SIXTY TO EIGHTY PERCENT DIGESTED BY TIME IT REACHES ILEUM ABSORPTION • ACTIVE TRANSPORT OF AMINO ACIDS, DIPEPTIDES, AND TRIPEPTIDES • DIPEPTIDASES AND TRIPEPTIDASES BREAK DOWN • AMINO ACIDS ENTER BLOOD STREAM LIPIDS • MAINLY TRIGLYCERIDES • DIGESTION PRIMARILY IN SMALL INTESTINE • EMULSIFICATION • BILE SALTS ESSENTIAL • FORMS MONOGYLCERIDES AND FREE FATTY ACIDS BILE SALTS • AMPHIPATHIC • FORM MICELLES • MONOGLYCERIDES AND FREE FATTY ACIDS BINDWITH BILE SALTMICELLES • TAKEN TO INTESTINAL EPITHELIUM ABSORPTION • MONOGLYCERIDES AND FREE FATTY ACIDS DISSOCIATE • ENTER EPITHELIAL CELLS BY SIMPLE DIFFUSION • BILE SALTS ARE REUSED • EVENTUALLY REABSORBED IN ILEUM INTESTINAL EPITHELIAL CELLS • MUCH OF THE MONOGLYCERIDES ARE BROKEN DOWN INTO GLYCEROL AND FATTY ACID • EPITHELIAL LIPASE IS THE ENZYME • IN ENDOPLASMIC RETICULM FREE FATTY ACIDS ARE AGAIN COMBINED WITH GLYCEROL • NEW GLYCEROL AND OLD GLYCEROL OTHER PRODUCTS • PHOSPHOLIPIDS • CHOLESTEROL • PROTEINS FATE OF PRODUCTS • PRODUCTS ARE PACKAGED IN MEMBRANE BOUND VESICLES • CONTAIN TRIGLYCERIDES, PHOSPHOLIPIDS, CHOLESTEROL AND SOME FREE FATTY ACIDS • EXOCYTOSIS • ENTER LACTEALS CHYLOMICRONS • • • • • ABOUT 90% TRIGLYCERIDES 5% PHOSPHOLIPIDS 4% FREE FATTY ACIDS 1% CHOLESTEROL SOME PROTEIN SITE OF ABSORPTION • DUODENUM • JEJUNUM • COMPLETED BY TIME REACHES ILEUM FATE OF INGESTED CHOLESTEROL • FREE CHOLESTEROL • CHOLESTEROL ESTERS • PANCREATIC CHOLESTEROL ESTERASE • FREE CHOLESTEROL ASSOCIATES WITH MICELLES AND IS ABSORBED VITAMIN ABSORPTION • FAT SOLUBLE • WATER SOLUBLE FAT SOLUBLE VITAMINS • • • • • • A D E K ASSOCIATE WITH MICELLES FAT REQUIRED FOR ABSORPTION WATER SOLUBLE • C • B (EXCEPT B12) • ABSORBED BY PASSIVE TRANSPORT VITAMIN B12 ABSORPTION • INTRINSIC FACTOR NECESSARY • PRODUCED BY STOMACH • ACTIVELY TRANSPORTED IN ILEUM MINERAL ABSORPTION • ACTIVE PROCESSES • PASSIVE PROCESSES ACTIVE TRANSPORT OF MINERALS • • • • • SODIUM POTASSIUM MAGNESIUM PHOSPHATE CHLORINE IN THE ILEUM--COUPLED TO BICARBONATE IONS PASSIVE TRANSPORT • CHLORIDE IN UPPER PART OF SMALL INTESTINE CALCIUM • ACTIVELY ALONG THE ENTIRE SMALL INTESTINE • ESPECIALLY IN DUODENUM • REQUIRES VITAMIN D WATER • SMALL INTESTINE CAN ABSORB 200400 ML OF WATER PER HOUR • 0.5 L OF WATER ENTERS COLON • SMALL INTESTINE ABSORBS ALMOST ALL THE WATER • MOVES ACCORDING TO OSMOTIC GRADIENT ABSORPTION IN LARGE INTESTINE • SODIUM ACTIVELY ABSORBED • CHLORIDE FOLLOWS PASSIVELY SECRETION IN LARGE INTESTINE • BICARBONATE IONS SECRETED WATER ABSORPTION • 300 - 400 ML WATER PER DAY • DUE TO SODIUM AND CHLORIDE TRANSPORT BACTERIA IN LARGE INTESTINE • GIANT FERMENTATION VESSEL • SYNTHESIZED IMPORTANT VITAMINS • USUALLY ONLY A SMALL AMOUNT OF OUR DIET FECAL MATERIAL • • • • WATER UNDIGESTED FOOD RESIDUE MICROORGANISMS EPITHELIAL CELLS EFFECT OF AGING ON THE DIGESTIVE SYSTEM • • • • • • • DIMINISHED SECRETIONS MUSCLES WEAKEN ATROPHY OF SALIVARY GLANDS TOOTH LOSS LOSS OF SENSATION OF TASTE SWALLOWING DIFFICULTIES DIVERTICULA
