DIGESTIVE SYSTEM
TRACT
INCLUDES ALL ORGANS INVOLVED IN:
o MASTICATION (CHEWING)
o DEGLUTITION (SWALLOWING)
o MIX FOOD WITH SALIVA
ANATOMY AND PHYSIOLOGY OF THE DIGESTIVE SYSTEM
ORAL CAVITY
· CHEEKS - BUCCAL
· LIPS - CHEIL/O, LABI/O
· HARD AND SOFT PALATE - PALAT/O
· PHARYNX - PHARYNG/O
· RUGAE - IRREGULAR RIDGES ON ANTERIOR HARD PALATE
· UVULA - SOFT TISSUE HANGING FROM SMALL PALATE; "SMALL GRAPE"
· TONGUE - LINGU/O, GLOSS/O
· TONSILS - TONSILL/O
· GUMS - GINGIV/O
TEETH - TERMS DESCRIBING SURFACES OF THE TEETH
· LABIAL - AGAINST TEETH
· BUCCAL - AGAINST CHEEK
· LINGUAL - AGAINST TONGUE (ALL TEETH)
· MESIAL - NEAREST TO MIDDLE
· DISTAL - FARTHEST FROM MIDDLE
· OCCLUSAL - TOP SURFACE
· INCISAL - SHARP EDGE ON INCISORS AND CUSPIDS
TOOTH
· CROWN - ABOVE GUM
· ROOT - EMBEDDED IN TOOTH SOCKET
· ENAMEL - OUTER, HARD PROTECTIVE LAYER
· DENTIN - BONY TISSUE MAKING UP BULK OF TOOTH (SOFTER THAN ENAMEL)
· CEMENTUM - PROTECTIVE LAYER COVERING DENTIN IN SOCKET
· PERIODONTAL MEMBRANE - SURROUNDS CEMENTUM; HOLDS TOOTH IN
· PULP - SOFT LAYER BELOW DENTIN. BLOOD VESSELS, NERVES, CONNECTIVE TISSUE AND LYMPH FOUND IN PULP (ROOT) CANAL
SALIVARY GLANDS - SEE TRANSPARENCY AND TEXT
PHARYNX - THROAT; COMMON PASSAGEWAY FOR FOOD AND AIR. BIFURCATES FORMING TRACHEA AND ESOPHAGUS
ESOPHAGUS - "THING TO SWALLOW INWARD"
- PERISTALSIS - SURROUNDING CONTRACTIONS
STOMACH
· FUNDUS - UPPER PORTION
· BODY - MIDDLE SECTION
· PYLORUS - LOWER PORTION
· CARDIAC SPHINCTER - JUNCTION OF ESOPHAGUS AND STOMACH
· PYLORIC SPHINCTER - JUNCTION OF STOMACH AND DUODEMUM
· STOMACH PRODUCES: HCl, PEPSIN - PROTEINS, LIPASE - FAT
· SMALL INTESTINE - ABOUT 20 FEET OF VILLI THAT ABSORB DIGESTED NUTRIENTS INTO BLOOD AND LYMPH
· DUODENUM - 1 FOOT; RECEIVES FOOD FROM STOMACH, BILE FROM LIVER AND GALL BLADDER; PANCREATIC JUICE FROM PANCREAS
· JEJUNUM - ABOUT 8'
· ILEUM - ABOUT 11'
LARGE INTESTINE/COLON - (LARGE BOWEL); ABOUT 5'
· FUNCTION - REABSORB WATER FROM WASTE PRODUCTS
· ANATOMY
· ILEOCECAL VALVE - JUNCTION OF ILEUM AND CECUM
· APPENDIX - NO CLEAR FUNCTION; APPENDICITIS
· ASCENDING COLON - EXTENDS UP TO LIVER
· TRANSVERSE COLON - HORIZONTALLY (LEFT) TO SPLEEN
· DESCENDING COLON - DOWN
· SIGMOID COLON - "S" SHAPED; DISTAL END OF DESCENDING COLON
· RECTUM - END OF COLON
· ANUS - LOWER OPENING OF THE GI TRACT
LIVER - FUNCTIONS
· BILE PRODUCTION - EMULSIFY FAT (PHYSICAL BREAKDOWN)
· DESTROY OLD RBC’s (RELEASE BILIRUBIN)
· REMOVE POISON FROM BLOOD (DETOXIFICATION)
· SYNTHESIS OF BLOOD PROTEINS, ESPECIALLY FOR CLOTTING
· GLUCOSE REGULATION
· NORMAL - EXCESS BLOOD GLUCOSE STORED IN LIVER CELLS AS GLYCOGEN
· GLYCOGENOLYSIS - LOW BLOOD SUGAR, GLYCOGEN CONVERTED TO GLUCOSE
· GLUCONEOGENESIS – WHEN NO AVAILABLE BLOOD GLUCOSE, LIVER CONVERTS PROTEINS AND FATS INTO GLUCOSE
LIVER, GALLBLADDER, PANCREAS
LIVER - RUQ; MAKES BILE WHICH CONTAINS CHOLESTEROL (FATTY MATERIAL), BILE ACIDS, AND SEVERAL BILE PIGMENTS
BILIRUBIN - BREAKDOWN PRODUCT OF HEMOGLOBIN; COMBINED WITH
BILE AND EXCRETED IN FECES
BILE TRAVELS DOWN HEPATIC DUCT TO CYSTIC DUCT WHICH LEADS TO GALLBLADDER WHERE IT IS STORED AND CONCENTRATED.
AFTER MEALS, BILE EXCRETED INTO COMMON BILE DUCT JOINS WITH PANCREATIC DUCT JUST PRIOR TO ENTERING THE DUODENUM.
PATHOLOGY OF THE DIGESTIVE SYSTEM
SYMPTOMS
ACHLORHYDRIA - CHRONIC GASTRITIS OR GASTRIC CARCINOMA
ANOREXIA - LACK OF APPETITE
DIARRHEA - SEE TEXT
DYSPHAGIA - MOVEMENT PROBLEMS IN ESOPHAGUS OR TUMOR/SWELLING BLOCKING PASSAGE OF FOOD
GASTROESOPHAGEAL REFLUX - HEARTBURN, POSSIBLY DUE TO HIATAL HERNIA
JAUNDICE/ICTERUS - ORANGE-YELLOW COLOR IN SKIN, ETC.
1. HEPATIC/HEPATOCELLULAR
2. POSTHEPATIC/OBSTRUCTIVE
3. PREHEPATIC/HEMOLYTIC
MELENA - BLACK, TARRY STOOLS DUE TO BLOOD IN FECES ABOVE THE DUODENUM
STEATORRHEA - FAT DISCHARGED IN FECES
PATHOLOGICAL CONDITIONS
APHTHOUS STOMATITIS (CANKER SORES) - SMALL, ORAL ULCERS
HERPETIC STOMATITIS (FEVER BLISTERS OR COLD SORES) - CAUSED BY HERPES VIRUS
ORAL LEUKOPLAKIA - WHITE PATCHES IN THE MOUTH; PRECANCEROUS
PERIODONTAL DISEASE - GINGIVITIS, POSSIBLY PYORRHEA; MAY REQUIRE GINGIVECTOMY
GASTROINTESTINAL TRACT
ANAL FISTULA - ABNORMAL PASSAGEWAY NEAR ANUS; MAY BE CONGENITAL, INJURY, INFECTION, METASTASIS, CHILDBIRTH
COLONIC POLYPOSIS - SMALL GROWTHS IN COLON
COLORECTAL CANCER - WARNING SIGNS: UNEXPLAINED CRAMPS OR ABDOMINAL BLEEDING, LEUKOCYTOPENIA, WEIGHT LOSS, BLOODY STOOLS
DIVERTICULA - OUTPOUCHING OF COLONIC MUCOSA; LOW RESIDUE DIETS MAY CONTRIBUTE TO CAUSE; MAY LEAD TO DIVERTICULITIS
DYSENTERY - PAINFUL INTESTINES; SEE TEXT
HERNIA - SEE TEXT; REVIEW CHAPTER 3
INTUSSUSCEPTION - TELESCOPED INTESTINES
VOLVULUS – TWISTED INTESTINES; MEDICAL EMERGENCY
IRRITABLE BOWEL SYNDROME - ASSOCIATED WITH STRESS,
SPASTIC COLON, NO PATHOLOGICAL LESIONS
ULCER - OPEN SORE/LESION OF EPITHELIAL TISSUE, E.G., GASTRIC OR PEPTIC ULCERS
ULCERATIVE COLITIS - CHRONIC INFLAMMATORY DISEASE; POSSIBLE DIARRHEA WITH BLOOD OR PUS; CAN BE DEBILITATING
LIVER, GALLBLADDER, AND PANCREAS
CIRRHOSIS - (CIRRH/O = ORANGE-YELLOW COLOR OF LIVER). CHRONIC, DEGENERATIVE DISEASE; LIVER TISSUE REPLACED WITH FIBROUS TISSUE RESULTING IN DETERIORATION OF ALL FUNCTIONS. OFTEN DUE TO ALCOHOL ABUSE, ALSO HEPATITIS, ETC.
GALLSTONES (CHOLELITHIASIS) - SEE BOOK
PANCREATITIS - INFLAMMATION DUE TO AUTODIGESTION OF TISSUES BY DIGESTIVE ENZYMES. ACUTE SYMPTOMS MIMIC APPENDICITIS, CHOLECYSTITIS, ULCERS. STEATORRHEA.
HEPATITIS -INFLAMMATION DUE TO DRUGS, CHEMICALS, ENVIRONMENTAL POISONS, ALCOHOL, PARASITES, VIRUSES - 3 MAJOR TYPES:
1. HEPATITIS A - ORAL/FECAL SPREAD, POOR HYGIENE AND SANITARY CONDITIONS, DOES NOT LEAD TO CHRONIC OR CARRIER STATE.
2. HEPATITIS B - MAINLY THROUGH TRANSFUSIONS OR CONTAMINATED NEEDLES; FOUND IN MOST BODY SECRETIONS; 5-10% BECOME CARRIERS OR CHRONIC
3. HEPATITIS C - MOSTLY THROUGH TRANSFUSIONS; GENERALLY MILD; 30-50% BECOME CHRONIC
DIGESTIVE DIAGNOSTIC/CLINICAL PROCEDURES
LIVER FUNCTION TESTS
SGOT, SGPT, ALK - ENZYMES NORMALLY FOUND IN LIVER TISSUE. INCREASED LEVELS INDICATE DAMAGE TO LIVER CELLS (ENZYMES LEAK INTO THE BLOOD).
BILIRUBIN - INCREASED LEVELS PRODUCE JAUNDICE (ICTERUS) IN SKIN AND OTHER TISSUES
STOOL CULTURES - FECAL MATERIAL IS PUT ON CULTURE MEDIA TO TEST FOR THE PRESENCE OF PATHOGENIC ORGANISMS
STOOL GUAIAC (HEMOCULT TEST) - TEST TO DETECT PRESENCE OF BLOOD IN FECES. TEST FOR MELENA OR OCCULT BLOOD
X-RAY TESTS
BARIUM ENEMA - DETECTS ABNORMALITIES IN THE LOWER GI TRACT
BARIUM SWALLOW - DETECTS ABNORMALITIES IN THE UPPER GI TRACT
CHOLANGIOGRAPHY - LOOK AT BILE VESSELS, E.G.,
PERCUTANEOUS TRANSHEPATIC CHOLANGIOGRAPHY
CT/CAT SCAN - CROSS-SECTIONAL/TRANSVERSE VIEW OF ABDOMEN
ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY - BACKWARD INJECTION OF DYE INTO BILE AND PANCREATIC DUCTS
ABDOMINAL ULTRASONOGRAPHY - SOUND WAVES PRODUCE IMAGES
RADIOACTIVE (LIVER SCAN) - IV INJECTION OF RADIOACTIVE MATERIAL. SCANNER RECORDS UPTAKE OF MATERIAL AND PRODUCES AN IMAGE
GASTROINTESTINAL ENDOSCOPY - SPECIAL TUBE PASSED THROUGH MOUTH OR ANUS FOR VISUAL EXAM.CAN ALSO REMOVE TISSUE, ETC.
LIVER BIOPSY - PERCUTANEOUS INSERTION OF NEEDLE INTO LIVER TO REMOVE TISSUE FOR MICROSCOPIC EXAM
NASOGASTRIC INTUBATION - USED TO REMOVE GASTRIC SECRETIONS AND ADMINISTER MEDICATIONS, FOOD, AND FLUIDS
PARACENTESIS (ABDOMINOCENTESIS) - REMOVE FLUID FROM PATIENT WITH ASCITES OR FOR DIAGNOSTIC PROCEDURES