PHARMACY PROGRAM NOVEMBER 2012 REV. PROF. A.S. AYETTEY

OBJECTIVES BE ABLE TO RECOGNIZE DIFFERENT PARTS OF THE DIGESTIVE SYSTEM (mouth, esophagus, stomach, duodenum, jejenum, ileum, large bowel, anal canal) BE ABLE TO RECOGNIZE THE FUNCTIONAL DESIGN OF THE DIGESTIVE SYSTEM BE ABLE TO RECOGNIZE THE FUNCTIONAL ROLE OF DIFFERENT PARTS OF THE DIGESTIVE SYSTEM BE ABLE TO WORK OUT CLINICAL PROBLEMS IN THE DIGESTIVE SYSTEM BASED ON YOUR KNOWLEDGE OF ITS FUNCTIONS

PARTS OF THE DIGESTIVE SYSTEM THE ORAL (buccal) CAVITY TEETH (mastication, defensive) TONGUE (aid in swallowing by rolling food, taste, sensory function- hot and cold receptors) PALATE (also has taste fibres, and aids in rolling food) SALIVARY GLANDS THE ORO-PHARYNX (immediately behind the oral cavity) THE ESOPHAGUS (10 INCHES; 25CM) THE STOMACH (digestion of proteins) DUODENUM – 10 INCHES; 25 CM LIVER GALL BLADDER PANCREAS JEJENUM 8 FEET; 2.5 METERS [absorption takes place mainly in the jejenum] ILEUM – 12 FEET; 3.6 METERS LARGE BOWEL – 5 FEET; 1.5 METERS [absorption of water and electrolytes and concentrate the waste into solid mass]

THE ROLE OF THE ORAL CAVITY 1 TEETH MASTICATION TO SOFTEN FOOD SPEECH TONGUE TASTE GENERAL SENSATION DEGLUTITION - swallowing SPEECH PALATE TASTE DEGLUTITION

ROLE OF ORAL CAVITY 2 SALIVARY GLANDS PAROTID GLANDS SUBMANDIBULAR GLANDS SUBLINGUAL GLANDS FUNCTIONS OF SALIVARY GLANDS LUBRICATION/MOISTEN FOOD SECRETION OF SALIVARY AMYLASE (STARCH TO GLUCOSE) SECRETION OF LYSOSYMES - ANTIBACTERIAL RELEASE OF ANTIBODIES – IMMUNOGLOBULIN A TO PROTECT THE MUCOSA

FUNCTIONS OF THE STOMACH RECEPTACLE FOR FOOD AND FLUIDS CAPACITY 2-4 LITRES PROTEIN DIGESTION PEPSINOGEN TO PEPSIN (pH 1-2) ABSORPTION OF WATER AND ELECTROLYTES ABSORPTION OF LIPID SOLUBLE SUBSTANCES ALCOHOL SOME DRUGS SUCH AS ASPIRIN CAFFEINE PRODUCTION OF INTRINSIC FACTOR ROLE IN ABSORPTION OF VITAMIN B12 PROPULSION OF FOOD INTO DUODENUM

GASTRIC SECRETIONS GASTRIC JUICE AND CONTENTS PARIETAL CELLS HYDROCHLORIC ACID (PARIETAL CELLS) ACTIVATES PEPSINOGEN SECRETION INACTIVATES INGESTED BACTERIA MUCUS (LUBRICATION AND PROTECTION) PEPSINOGEN (ENZYME) PEPSIN (INITIATION OF PROTEIN DIGESTION) GASTRIN (HORMONE) STIMULATES SECRETION OF ACID INCREASES GASTRIC MOTILITY GLYCO-PROTEIN INTRINSIC FACTOR (GLYCO-PROTEIN) ABSORPTION OF VITAMIN B12 IN THE ILEUM (without intrinsic factor there cannot be vit. B12 absorption) FOR ABSORPTION OF VITAMIN B12 IN THE ILEUM (without intrinsic factor there cannot be vit. B12 absorption)

FUNCTIONS OF THE DUODENUM RECEIVES FOOD-chyme (rich in lipids, starch, amino acids) FROM STOMACH REGULATES FOOD ENTRY FROM STOMACH SECRETES HORMONES COMPLETES PROCESSES OF DIGESTION OF PROTEINS AND CARBOHYDRATES BEGINS THE PROCESS OF ABSORPTION IRON ABSORPTION OCCURS PRIMARILY HERE

DUODENAL GLAND SECRETIONS BRUNNERS GLANDS MUCUS RICH ALKALINE SECRETION DEACTIVATES PEPSINOGEN PROTECTS DUODENUM FROM GASTRIC SECRETIONS HORMONES SECRETIN STIMULATES BICARBONATE SECRETION FROM THE LIVER AND PANCREAS TO REGULATE pH TRIGGERS INSULIN SECRETION TO REGULATE GLUCOSE CHOLECYSTOKININ PEPTIDE HORMONE RESPONSIBLE FOR DIGESTION OF FAT CONTRIBUTES TO DIGESTION OF PROTEINS UROGASTRONE INHIBITS SECRETION OF ACID AND PEPSINOGEN

FUNCTIONS OF THE PANCREAS EXOCRINE FUNCTIONS PRODUCING DIGESTIVE JUICES THAT CONTAIN ALKALINE FLUID (BICARBONATES) CHYMOTRYPSIN (BREAKDOWN OF PROTEINS AND POLYPEPTIDES) LIPASE (HYDROLYSIS OF LIPIDS) AMYLASE (DIGESTION OF STARCH ends in the duodenum). ENDOCRINE FUNCTIONS – HORMONE PRODUCTION INSULIN (LOWERS BLOOD GLUCOSE LEVEL) GLUCAGON (INCREASES BLOOD SUGAR LEVEL) SOMATOSTATIN (INHIBITS RELEASE OF GROWTH HORMONE AND THYROID STIMULATING HORMONE)

FUNCTIONS OF THE LIVER PLASMA PROTEINS – ALBUMIN, GLOBULIN, FIBRINOGEN(blood clotting) GLUCOSE METABOLISM(can mobilise glucose when level is low) DEAMINATION (removal of amine group) OF AMINO ACIDS – TO FORM UREA(to be excreted in the kidneys) CONVERSION OF AMMONIA TO UREA FORMATION OF BLOOD CLOTTING FACTORS – I(FIBRINOGEN) II (PROTHROMBIN), IV, V, VI, VII PROTEIN AND LIPID SYNTHESIS/CHOLESTEROL (abt 25%) STORAGE OF GLUCOSE, IRON AND VITAMINS A,D,E,K AND B12 BREAKDOWN OF HAEMOGLOBIN TO IRON AND BILE DETOXIFICATION/METABOLISM OF DRUGS

THE GALL BLADDER ATTACHED TO THE LIVER RECEIVES BILE SECRETED BY THE LIVER STORES BILE CONCENTRATES BILE SECRETES BILE FOR FAT DIGESTION THROUGH THE COMMON BILE DUCT INTO THE DUODENUM ASSOCIATED WITH CLINICAL PROBLEMS GALL STONES GALL BLADDER INFECTIONS CANCER OF THE GALL BLADDER

FUNCTIONS OF THE JEJUNUM AND ILEUM FUNCTIONS OF JEJENUM ABSORPTION OF PRODUCTS OF DIGESTION GLUCOSE AMINO ACIDS FATTY ACIDS ABSORPTION OF WATER SOLUBLE VITAMINS – THE B SERIES & VITAMIN C (EXCEPT B12) REMAINING IRON ABSORPTION OF REMAINING IRON ABSORPTION OF SODIUM FUNCTIONS OF THE ILEUM ABSORPTION OF B12 (AIDED BY INTRINSIC FACTOR) FAT SOLUBLE VITAMINS – A;D;K & E BILE SALTS ABSORPTION WATER IMMUNOLOGIC FUNCTIONS (PEYERS PATCHES) – bacteria that must have escaped the GIT are destroyed by lymphocytes present in the Peyers patches in the ileum especially at the ileo-caecal junction.

FUNCTIONS OF THE LARGE BOWEL STORAGE OF WASTE MATTER ABSORPTION OF WATER ABSORPTION OF ELECTROLYTES FORMATION OF FAECES ABSORPTION OF SOME VITAMINS SUCH AS VIT K PROPULSION OF WASTE MATERIAL TO THE ANUS DEFAECATION