1. THE DIGESTIVE SYSTEM
EDILBERTO A. RAYNES, MD

2. ORGANS OF THE DIGESTIVE SYSTEM
MAIN ORGAN
ACCESSORY ORGAN

3. MAIN ORGAN MOUTH PHARYNX (THROAT) ESOPHAGUS (FOODPIPE) STOMACH
SMALL INTESTINE (DUODENUM, JEJUNUM, ILEUM)
LARGE INTESTINE (CECUM; COLON: ASCENDING, TRANSVERSE, DESCENDING, SIGMOID; RECTUM; ANAL CANAL)

4. ACCESSORY ORGAN TEETH AND TONGUE
SALIVARY GLANDS (PAROTID, SUBMANDIBULAR, SUBLINGUAL)
LIVER
GALLBLADDER
PANCREAS
VERMIFORM APPENDIX

5. FUNCTIONS OF DIGESTIVE SYSTEM
INGESTION
DIGESTION
ABSORPTION
DEFECATION

7. PERITONEUM ENVELOPS THE ENTIRE ABDOMINAL WALL
LARGEST SEROUS MEMBRANE IN THE BODY
THE FREE SURFACE IS LUBRICATED WITH A SEROUS FLUID THAT ALLOWS THE DIGESTIVE STRUCTURES AND OTHER VISCERAL ORGANS TO GLIDE EASILY AGAINST THE ABDOMINAL WALL WITHOUT FRICTION

8. PERITONEUM CONTAINS BLOOD VESSELS, LYMPH VESSELS AND NERVES
INCLUDES MESENTERIES, PARIETAL AND VISECERAL PERITONEUM, GREATER AND LESSER OMENTUM

10. WALL OF DIGESTIVE TRACT: FOUR LAYERS
MUCOSA OR MUCOUS MEMBRANES-MUCOUS EPITHELIUM
SUBMUCOSA- CONNECTIVE TISSUE LAYER; BLOOD VESSELS AND NERVES
MUSCULARIS: 2 OR 3 LAYERS OF SMOOTH MUSCLE; PERISTALSIS
SEROSA-OUTERMOST COVERING; VISCERAL EPITHELIUM; ATTACHES THE DIGESTIVE TRACT TO THE WALL OF THE ABDOMINOPELVIC CAVITY BY FORMING FOLDS CALLED MESENTERIES

12. MOUTH OR ORAL CAVITY ROOF FORMED BY THE HARD AND SOFT PALATES
HARD PALATE: PARTS OF MAXILLARY AND PALATINE BONES
SOFT PALATE: ARCH-SHAPED MUSCLE SEPARATING MOUTH FROM PHARYNX
UVULA: DOWNWARD PROJECTION OF THE SOFT PALATE

13. MOUTH OR ORAL CAVITY FLOOR FORMED BY TONGUE AND ITS MUSCLES
•SKELETAL MUSCLE
•FRENULUM: ATTACHES THE TONGUE TO
•PAPILLAE: SMALL ELEVATIONS
-VALLATE: LARGEST
-TASTE BUDS: SENSORY RECEPTORS

14. TEETH TYPES: INCISORS: MASTICATION OR CHEWING
CANINES (CUSPIDS): PIERCING OR TEARING
PREMOLARS OR BICUSPIDS
MOLARS OR TRICUSPIDS

15. TEETH AT AGE 2, 20 TEETH IN TEMPORARY SET
AT AGE BETWEEN 17 AND 24, 32 PERMANENT TEETH
TYPICAL TOOTH
1. CROWN
2. NECK
3. ROOT

16. SALIVARY GLANDS
PAROTID GLAND: LARGEST; LIE BELOW AND IN FRONT OF EACH EAR AT THE ANGLE OF THE JAW; DUCT OPENS AT THE OPPOSITE THE 2ND MOLAR TOOTH ON EITHER SIDE OF THE UPPER JAW
SUBMANDIBULAR: ON EITHER SIDE OF THE LINGUAL FRENULUM
SUBLINGUAL
*SALIVA CONTAINS MUCUS AND A DIGESTIVE ENZYME THAT IS CALLED SALIVARY AMYLASE

18. PHARYNX
MUSCULAR TUBE THAT FUNCTIONS AS PART OF THE RESPIRTORY AND DIGESTIVE SYSTEMS

19. ESOPHAGUS MUCUS LINED TUBE BETWEEN PHARYNX AND STOMACH
*HIATAL HERNIA: THE STOMACH PUSHES THROUGH THE GAP IN THE DIAPHRAGM THAT ALLOWS THE ESOPHAGUS BECOMES ENLARGED, ALLOWING ACIDIC STOMACH CONTENTS TO BYPASS A VALVELIKE SPHINCTER MUSCLE AND FLOW UPWARD INTO THE ESOPHAGUS

21. STOMACH
LIES IN THE UPPER PART OF THE ABDOMINAL CAVITY JUST UNDER THE DIAPHRAGM
LOWER ESOPHAGEAL OR CARDIAC SPHINCTER KEEPS THE FOOD FROM REENTERING THE ESOPHAGUS WHEN THE STOMACH CONTRACTS
CONTRACTION OF THE STOMACH’S MUSCULAR WALLS MIXES THE FOOD THOROUGHLY WITH THE GASTRIC JUICE AND BREAKS IT DOWN INTO A SESAMOID MIXTURE CALLED CHYME.

22. STOMACH
MUSCLE CONTRACTION RESULTS IN PERISTALSIS THAT PROPELS FOOD DOWN THE DIGESTIVE TRACT TOGETHER WITH THE GASTRIC JUICE AND HYDROCHOLORIC ACID INTO THE STOMACH
PARTS: FUNDUS, BODY, PYLORUS
LESSER CURVATURE: UPPER RIGHT BORDER
GREATER CURVATURE: LOWER LEFT BORDER

23. STOMACH THE GASTRIC MUCOSA CONTAINS ENDOCRINE AND EXOCRINE CELLS.
G CELLS: ENDOCRINE CELLS THAT SECRETE HORMONE GASTRIN, WHICH INITIATES THE PRODUCTION AND SECRETION OF GASTRIC JUICE AND STIMULATES BILE AND PANCREATIC ENZYMES INTO THE SMALL INTESTINE

24. STOMACH 2 TYPES OF EXOCRINE CELLS: PARIETAL AND CHIEF CELLS
PARIETAL CELLS: PRODUCE (1) INTRINSIC FACTOR, A SUBSTANCE REQUIRED FOR THE ABSORPTION OF VITAMIN B12 FROM THE SMALL INTESTINE TO THE BLOODSTREAM; (2) HYDROCHOLORIC ACID, WHICH BREAKS DOWN PROTEIN AND ACTIVATES MANY GASTRIC ENZYMES

25. STOMACH
CHIEF CELLS: PRODUCE GASTRIC ENZYME, PEPSINOGEN, A PRECURSOR TO PEPSIN. PEPSIN IS SECRETED IN AN INACTIVE FORM TO PREVENT THE GASTRIC LINING FROM ERODING FROM PEPSIN’S PROTEIN DIGESTION. PEPSINOGEN CONVERTS TO PEPSIN WHEN IT COMES IN CONTACT WITH HCL AND BEGINS THE CHEMICAL DIGESTION OF PROTEINS BY CONVERTING THEM INTO PEPTIDES

26. STOMACH
CHYMOSIN OR RENNIN, AN ENZYME PRESENT IN THE GASTRIC JUICES OF INFANTS, IS USED TO AID IN MILK CURDLING AND IS USED COMMERCIALLY TO PRODUCE CHEESE.

27. SMALL INTESTINE DIVISIONS: DUODENUM, JEJUNUM, ILEUM
WALL CONTAINS SMOOTH MUSCLE FIBERS THAT CONTRACT TO PRODUCE PERISTALSIS
LINED BY MUCOUS MEMBRANES
INTESTINAL GLANDS: INTESTINAL JUICE
VILLI: FINGER-SHAPED PROJECTIONS THAT CONTAIN BLOOD AND LYMPH CAPILLARIES THAT ABSORB THE PRODUCTS OF CARBOHYDRATE AND PROTEIN DIGESTION

29. LIVER LARGEST GLAND SECRETE BILE HEPATIC DUCTS: DRAINS BILE FROM LIVER
CYSTIC DUCT: BILE ENTERS AND LEAVES GALLBLADDER
COMMON BILE DUCT: UNION OF HEPATIC AND CYSTIC DUCT; DRAINS BILE FROM HEPATIC OR CYSTIC DUCTS INTO DUODENUM

30. BILE MECHANICALLY BREAKS UP OR EMULSIFIES FATS
WHEN CHYME CONTAINING LIPID OR FAT ENTERS THE DUODENUM, IT INITIATES A MECHANISM THAT CONTRACTS THE GALLBLADDER AND FORCES THE BILE INTO THE SMALL INTESTINE

31. BILE
FATS IN CHYME TRIGGER THE SECRETION OF THE HORMONE CHOLECYSTOKININ (CCK) FROM THE INTESTINAL MUCOSA OF THE DUODENUM. CCK STIMULATES THE CONTRACTION OF THE GALLBLADDER AND BILE FLOWS INTO THE DUODENUM

32. GALLBLADDER LOCATED UNDER THE SURFACE OF THE LIVER
CONCENTRATES AND STORES BILE PRODUCED IN THE LIVER

33. PANCREAS BEHIND THE STOMACH FUNCTIONS:
1. PANCREATIC CELLS SECRETE PANCREATIC JUICE INTO PANCREATIC DUCTS; MAIN DUCTS EMPTIES INTO DUODENUM
2. PANCREATIC ISLETS OF LANGERHANS: CELLS NOT CONNECTED WITH PANCREATIC DUCTS; SECRETE HORMONES GLUCAGON AND INSULIN INTO THE BLOOD

35. LARGE INTESTINE
DIVISIONS: CECUM; COLON (ASCENDING, TRANSVERSE, DESCENDING AND SIGMOID); RECTUM
WALL: SMOOTH MUSCLE FIBERS THAT CONTRACT TO PRODUCE CHURNING, PERISTALSIS AND DEFECATION

36. FUNCTIONS OF LARGE INTESTINE
ABSORPTION OF WATER AND CERTAIN ELECTROLYTES
SYNTHESIS OF CERTAIN VITAMINS BY THE INTESTINAL BACTERIA (ESPECIALLY VITAMIN K AND CERTAIN B VITAMINS)
TEMPORARY STORAGE SITE OF WASTE (FECES)
ELIMINATION OF WASTE FROM THE BODY (DEFECATION)

37. APPENDIX BLIND TUBE OFF CECUM
NO IMPORTANT DIGESTIVE FUNCTION IN HUMANS

40. PROCESSING OF FOOD
DIGESTION
ABSORPTION
METABOLISM

41. DIGESTION
CHANGING FOODS SO THAT THEY CAN BE ABSORBED AND USED BY CELLS
TYPES: MECHANICAL, CHEMICAL, CARBOHYDRATE, PROTEIN, FAT DIGESTION

42. MECHANICAL DIGESTION
CHEWING, SWALLOWING AND PERISTALSIS BREAK FOOD INTO TINY PARTICLES
MIX WELL WITH DIGESTIVE JUICES
MOVE THEM ALONG THE DIGESTIVE TRACT

43. CHEMICAL DIGESTION
BREAKS UP LARGE FOOD MOLECULES INTO COMPOUNDS HAVING SMALLER MOLECULES
BROUGHT ABOUT BY DIGESTIVE ENZYMES

44. CARBOHYDRATE DIGESTION
MAINLY IN SMALL INTESTINE
PANCREATIC AMYLASE: CHANGES STARCHES TO MALTOSE
INTESTINAL JUICE ENZYMES
1. MALTASE: CHANGES MALTOSE TO GLUCOSE
2. SUCRASE: SUCROSE TO GLUCOSE
3. LACTASE: LACTOSE TO GLUCOSE

45. PROTEIN DIGESTION STARTS IN STOMACH; COMPLETED IN SMALL INTESTINE
GASTRIC JUICE ENZYMES, RENNIN AND PEPSIN: PARTIALLY DIGEST PROTEINS
PANCREATIC ENZYME, TRYPSIN: COMPLETES DIGESTION OF PROTEINS TO AMINO ACIDS
INTESTINAL ENZYMES, PEPTIDASES: COMPLETE DIGESTION OF PARTIALLY DIGESTED PROTEINS TO AMINO ACIDS

46. FAT DIGESTION
BILE CONTAINS NO ENZYMES BUT EMULSIFIES FATS (BREAKS FAT DROPLETS INTO VERY SMALL DROPPLETS)
PANCREATIC LIPASE: CHANGES EMULSIFIED FATS TO FATTY ACIDS AND GLYCEROL IN SMALL INTESTINE

47. ABSORPTION DIGESTED FOOD MOVES FROM INTESTINE INTO BLOOD OR LYMPH
FOODS AND MOST WATER FROM SMALL INTESTINE
WATER FROM LARGE INTESTINE