Digestive System Notes PDF

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Description

Digestive System Key Terminology: Term

Meaning Anus, ring Bile, gall Gall bladder Colon, large intestine Vomiting Small intestine Esophagus Stomach, belly Liver Presence of stones Digest, digestion Eating, swallowing Anus and rectum Rectum, straight Sigmoid colon

An/o Chol/e Cholecyst/o Col/o, colon/o -emesis Enter/o Esophag/o Gastr/o Hepat/o -lithiasis -pepsia -phagia Proct/o Rect/o Sigmoid/o

Other Medical Terms:                     

Aerophagia Anastomosis Anorexia nervosa Antiemetic Aphthous ulcers Ascites Bariatrics Borborygmous Bulimia nervosa Cachexia Celiac disease Cheilosis Cholangiography Cholangitis Cholecystectomy Cholecystitis Choledocholithoto my Cholelithiasis Cirrhosis Colonoscopy Colostomy

Anatomy/Physiology:

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Crohn’s disease Diverticulitis Diverticulosis Dyspepsia Dysphagia Enteritis Eructation Esophageal varices Esophagogastroduo denoscopy Gastroduodenosto my Gastroesophageal reflux disease Gastrotomy tube Hematemesis Hemoccult test Hepatitis Herpes labialis Hiatal hernia Hyperemesis Ileus

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Inguinal hernia Jaundice Leukoplakia Melena Morbid obesity Nasogastric intubation Obesity Palatoplasty Peptic ulcers Peristalsis Polyp Proctologist Regurgitation Salmonellosis Sigmoidoscopy Stomatitis Trismus Ulcerative colitis Volvulus Xerostomia

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Composed of gastrointestinal tract and accessory organs o Upper GI tract: mouth, pharynx, esophagus, stomach o Lower GI tract: intestines, rectum, anus Oral Cavity: Mouth opening → lips, palates, salivary glands, tongue, teeth, periodontium o Lips: surround opening of oral cavity → hold food in mouth o Palate: forms roof of mouth  Hard palate: anterior portion of palate (covered in special mucous membrane) → consist of rugae (folds/ridges in membrane)  Soft palate: flexible posterior palate → closes nasal cavity during swallowing  Uvula: hangs from free edge of soft palate → moves upwards with soft palate during swallowing (role in snoring + speech) o Tongue: strong, flexible, muscular (anterior is free, posterior is attached to oral cavity)  Upper surface → dorsum → covered in small bumps (papillae) which contain taste buds  Sublingual surface + other tissues → covered with delicate vascular tissues  Lingual frenum: tissue attaching tongue to floor of mouth o Periodontium: structures supporting/attached to teeth (dental arches + surrounding tissue) o Gingiva: mucous membrane covering bone of dental arches + surroundings neck of teeth o Dental arches: bony structures of oral cavity  Maxillary arch: upper jaw → bones of lower skull → doesn’t move  Mandibular arch: lower jaw → movable  Temporomandibular joint: formed at back of mouth → intersection of maxillary and mandibular arches o Dentition: natural teeth arranged in jaws  Incisors and canines: biting and tearing  Premolars and molars: chewing and grinding  Primary dentition: 20 baby teeth  Permanent dentition: 32 adult teeth  Occlusion: contact between chewing surfaces of lower + upper teeth o Teeth  Crown = visible portion of tooth → covered in enamel (hardest substance in body)  Roots: hold teeth in place in dental arch → protected by cementum  Cervix: meeting of crown and roots  Dentin: majority of tooth  Pulp cavity: area in crown + roots surrounded by dentin → also root canals  Pulp: rich supply of blood vessels and nerves o Saliva: colorless liquid maintaining moisture + lubricating food for digestion o Salivary glands: secrete saliva through ducts  Parotid glands: located on face in front of ear

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 Sublingual glands: located on floor of mouth under tongue  Submandibular glands: floor of mouth near mandible Pharynx: important role in swallowing (deglutition) Epiglottis: lid-like structure → prevents food + liquid from entering trachea Esophagus: muscular tube where food passes from pharynx to stomach o Lower esophageal sphincter: ring between esophagus and stomach → relaxes during swallowing + closes to prevent regurgitation Stomach: sac-like organ composed of fundus, body, antrum o Rugae: folds in mucosa lining of stomach (glands produce gastric juices) o Gastric juices: aid in food digestion o Pyloric sphincter: muscle at base of stomach → controls flow of partially digested food to duodenum of small intestine o Pylorus: narrow passage connecting stomach with small intestine Small intestine: extends from pyloric sphincter to large intestine (20 feet) o Duodenum: extends from pylorus to jejunum o Jejunum: extends from duodenum to ileum o Ileum: extends from jejunum to cecum of large intestine Large intestine: extends from small intestine to anus (2x wide but 1/4x long) → waste production o Cecum: pouch on right side of abdomen → end of ileum to beginning of colon  Ileocecal sphincter: muscle controlling flow from ileum to cecum  Vermiform appendix: hangs from lower portion of cecum (lymphoid tissue) o Colon: longest part of large intestine → cecum to rectum  Ascending colon: upward from cecum to underside of liver  Transverse colon: horizontal across abdominal cavity → right to left towards spleen  Descending colon: downwards abdominal cavity → left side to sigmoid colon  Sigmoid colon: s-shaped structure extending from descending colon to rectum o Rectum: widest division of large intestine → ends at anus o Anus: lower opening of digestive tract → flow of waste controlled by internal + external anal sphincter o Anorectal: pertaining to anus and rectum Accessory organs: key role in digestion → not part of GI tract o Liver: largest organ in body → toxin removal + bile production  Removes excess glucose → stored as glycogen (starch)  Bilirubin: yellow/green fluid manufactured by liver → fat digestion  Bile: secreted by liver → concentrated and stored in gallbladder  Biliary tree: channels for bile transportation  Common hepatic duct: trunk outside liver  Cystic duct: exiting gallbladder  Common bile duct: common hepatic duct + cystic duct meeting with pancreatic duct

o Gallbladder: pear-shaped organ under liver → stores bile for later use  Cholecystic: pertaining to gallbladder o Pancreas: oblong gland located behind stomach → secrete juices containing enzymes that travel into duodenum via pancreatic duct 

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Digestion: breakdown of food into nutrients for use by body o Digestive enzymes: chemical changes in food breakdown o Nutrient: carb, fat, protein, vitamin, mineral that help with body function Metabolism: all processes involving use of nutrients o Anabolism: building up of body cells and substances from nutrients o Catabolism: breaking down of body cells and substances releasing energy + carbon dioxide Absorption: digested nutrients transported to cells throughout body o Villi: hairs lining mucous membranes → contain blood vessels and lacteals → diffusion into bloodstream  Lacteals: absorb fats + vitamins for transport via lymphatic vessels Mastication: breaking down of food into smaller pieces + mixing with saliva Bolus: mass of food chewed and ready to be swallowed Peristalsis: wave-like contractions of smooth muscles in downward direction to push food forward Chyme: semifluid mass of partly digested food passing out of stomach → formed from churning motion of stomach with acids Emulsification: breaking down of fat globules through pancreatic juices and bile o Jejunum: continues digestion o Ileum: absorption of nutrients Feces: expelled through rectum and anus → waste matter with water absorbed in large intestine Defecation: evacuation/emptying of large intestine Borborygmus: rumbling noise caused by movement of gas in intestine Flatulence: passage of gas out of body through rectum

Diseases:         

Aphthous ulcers: gray-white pits with red border in soft tissues of mouth → stress, fever, certain foods Ulcer: open lesion of skin or mucous membrane → tissue loss around edges Cheilosis: disorder of lips → crack-like sores at corners of mouth Herpes labialis: blister-like sores on lips and facial tissues caused by HSV-1 → cold sores Leukoplakia: abnormal white precancerous lesion → tongue or inside of cheek → response to constant irritation Stomatitis: inflammation of mucosa of the mouth Stomatomycosis: disease of mouth due to a fungus Oral thrush: stomatomycosis from out of control candida albicans → creamy white lesions Trismus: restriction to opening of mouth → treatment of oral cancer

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Xerostomia: lack of adequate saliva due to diminished secretions Cleft lip: deep groove of lip running upward to nose → failure to close during prenatal development Cleft palate: failure of palate to close in fetus → difficulty in speech and eating Bruxism: involuntary grinding and clenching of teeth during sleep → tension and stress Dental caries: infectious disease caused by bacteria → destruction of enamel and dentin Dental plaque: soft deposits near gums and between teeth (bacteria) Edentulous: without teeth Halitosis: unpleasant odor coming from mouth → dental or gastric disorders Malocclusion: deviation from normal positioning of upper and lower teeth Periodontal disease: inflammation of tissues surrounding teeth o Dental calculus: dental plaque calcified on teeth → causes severe periodontal diseases o Gingivitis: inflammation of the gums (earliest stage of periodontal disease) o Acute necrotizing ulcerative gingivitis: abnormal bacteria growth in mouth → inflammation of gums + formation of ulcers in mouth → mouth tissue death Dysphagia: difficulty swallowing Gastroesophageal reflux disease: upward flow of acid from stomach to esophagus (damage to lining) Barrett’s esophagus: epithelial cell damage in esophagus → prolonged acid exposure Pyrosis: burning sensation from return of acidic stomach contents into esophagus Esophageal varices: enlarged, swollen veins at lower end of esophagus Hiatal hernia: portion of stomach protrudes upwards into chest → opening in diaphragm Gastritis: inflammation of stomach lining (bacteria Helicobacter pylori) Gastroenteritis: inflammation of mucous membrane lining stomach and intestine Gastrorrhea: excessive secretion of gastric juice/mucus in stomach Peptic Ulcers: sores affecting mucous membranes → bacterial infection = high irritation o Gastric Ulcers: ulcers in stomach o Duodenal Ulcers: ulcers in upper part of small intestine o Perforating Ulcer: ulcer erodes through thickness of organ wall Anorexia: loss of appetite for food Anorexia nervosa: eating disorder → false perception of body appearance (fear of getting fat → voluntary starvation + excessive exercising) Bulimia nervosa: eating disorder → heavy binge eating + self-induced vomiting/use of laxatives Cachexia: physical wasting away → loss of weight and muscle → cancer and AIDS Pica: abnormal craving for nonfood substances (1 month) Dehydration: fluid loss exceeds fluid intake → bad electrolyte balance Malnutrition: lack of nutrients/food in body → shortage in food or bad eating habits Malabsorption: small intestine cannot absorb nutrients from food passing through it Obesity; excessive accumulation of fat in body (20%-30% above normal weight) o Morbid Obesity: weighing 2x the established weight or having body mass index > 40 o Body Mass Index: body weight adjusted for height (underweight, normal, overweight, obese) o Comorbidity; presence of 1+ health condition in an individual at a time

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Aerophagia: excessive swallowing of air while eating or drinking (gas in stomach) Dyspepsia: pain or discomfort in digestion Emesis: reflex ejection of stomach contents through the mouth Eructation: belching or raising gas orally from stomach Hematemesis: vomiting of blood Hyperemesis: excessive, persistent vomiting → dehydration Nausea: urge to vomit Regurgitation: return of swallowed food into mouth Celiac disease: autoimmune disorder → severe reaction to foods containing gluten → damages villi = lack of absorption into body Colorectal carcinoma: colon cancer → polyps in colon Polyp: mushroom-like growth from surface of mucous membrane Diverticulosis: chronic presence of abnormal diverticula count in colon Diverticulum: pouch/sac found in lining/wall of a tubular organ Diverticulitis: inflammation/infection of 1+ diverticula in the colon Enteritis: inflammation of small intestine → eating food/water with pathogens Ischemic colitis: parts/whole of large intestine is derived of blood → can lead to inflammation Ileus: partial/complete blockage of small/large intestine → stops peristalsis o Postoperative ileus: impairment of bowel movement in response to abdominal surgery Irritable Bowel Syndrome: not pathogenic → cramping, diarrhea, constipation → stress + various foods Inflammatory Bowel Disease: diseases causing inflammation/swelling in intestines (occur at flares with alternating periods of remission) o Ulcerative colitis: repeated inflammation of rectum and large intestine → ulcers + irritation  Affects innermost lining, not deep tissues → travels upwards to lower colon generally o Crohn’s disease: chronic autoimmune disease → found in ileum and colon → affects all tissue in affected area = scarring + thickening of walls Intestinal obstruction: partial/complete blockage of small/large intestine from physical obstruction o Intestinal adhesion: separate parts of intestine are held together (obstruction) o Gangrene: tissue death caused by lack of circulation (strangulating obstruction) o Volvulus: twisting of intestine on itself o Intussusception: telescoping of intestine into opening of adjacent part o Inguinal hernia: protrusion of loop of bowel through weak place in lower abdominal wall/groin o Strangulated hernia: portion of intestine is constricted inside hernia → causing ischemia in tissue Clostridium difficile: bacterial infection → following use of antibiotics wiping out other bacteria Dysentery: bacterial infection → hot countries → spread through water contaminated with human feces E. coli: transmitted through uncooked foods (Escherichia coli bacterium)

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Salmonellosis: transmitted by feces or raw/undercooked foods Anal fissure: crack-like sore in skin of anus → severe pain during bowel movement Bowel incontinence: inability to control excretion of feces Constipation: bowel movement fewer than 3 times a week → hard, dry, small stools Diarrhea: frequent flow of loose/watery stools → dehydration Hemorrhoids: cluster of veins/muscles/tissues slip near/through anal opening → inflammation + pain Rectocele: bulging of rectum into vagina → childbirth/pregnancy Hematochezia: flow of bright red blood into stool (lower GI tract) Melena: passage of black, tarry, foul-smelling stools → digested blood (upper GI tract) Steatorrhea: excess of fat in stool → frothy, foul-smelling feces Ascites: accumulation of serous fluid in peritoneal cavity Hepatomegaly: abnormal enlargement of the liver Jaundice: yellow discoloration of skin, mucous membrane, eyes → excess bilirubin in blood Hepatitis: inflammation of liver → viral infection o Hepatitis A virus: transmitted through food/water with fecal matter o Hepatitis B virus: bloodborne disease (and body fluids) o Hepatitis C virus: incurable bloodborne disease → full destruction of liver Cirrhosis: degenerative disease of liver → scarring + scarred tissue formation (filled with fat) Nonalcoholic fatty liver disease: accumulation of fat in liver → no alcohol consumption Nonalcoholic steatohepatitis: fatty accumulations and liver-damaging inflammation Cholangitis: inflammation of bile duct → pain in upper right quadrant of abdomen Cholecystitis: inflammation of gallbladder (gallstones) Gallstone: hard deposit formed in gallbladder → concretion of bile components Cholelithiasis: presence of stones in gallbladder or bile ducts Biliary colic: passage of gallstone through bile duct

Treatments/Procedures:        

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Abdominal computed tomography: produces cross-section of tissue within abdomen Abdominal ultrasound: visualizing internal organs through high-frequency sound waves Cholangiography: radiographic examination of bile ducts (contrast medium) Enema: placement of solution into rectum to empty lower intestine through bowel activity Esophagogastroduodenoscopy: endoscopic procedure → upper GI tract Upper + lower GI series: radiographic studies examining digestive system (contrast medium) Stool samples: specimen of feces to identify characteristics + diseases Endoscope: instrument used for visual examination of internal structures o Anoscopy: visual examination of anal canal and lower rectum o Capsule endoscopy: use of tiny video camera that patient swallows Colonoscopy: visual examination of inner surface of colon from rectum to cecum Sigmoidoscopy: endoscopic examination of interior of rectum, sigmoid colon, descending colon Hemoccult test: laboratory test for hidden blood in stools

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Antacids: neutralize stomach acid → relieves heartburn or helps heal peptic ulcers Proton pump inhibitors: decrease amount of acid produced by stomach Antiemetic: medication administered to prevent/relieve nausea and vomiting Laxatives: medications/foods stimulating bowel movement Intravenous fluids: combat effects of dehydration Oral rehydration therapy: solution of electrolytes (liquid) is administered orally to relieve dehydration Dental prophylaxis: professional cleaning of teeth to remove plaque and calculus Gingivectomy: surgical removal of diseased gingival tissue Maxillofacial surgery: specialized surgery of face and jaws (deformities, disease, injuries) Palatoplasty: surgical repair of cleft palate/cleft lip Gastrectomy: surgical removal of all/part of stomach Nasogastric intubation: placement of feeding tube through nose into stomach Gastrostomy tube: feeding tube from exterior placed directly into stomach Total parenteral nutrition: administered to patients who cannot/should not get nutrients through eating Bariatric surgery: treats morbid obesity → restricting amount of food that can enter stomach o Gastric bypass surgery: makes stomach smaller → stapling section to create pouch → food bypasses first part of small intestine o Lap-band adjustable gastric banding: band around exterior of stomach to restrict amount of food that can enter/be digested Colectomy: surgical removal of colon Colotomy: surgical incision into the colon Diverticulectomy: surgical removal of a diverticulum Gastroduodenostomy: establishment of anastomosis between upper stomach and duodenum Anastomosis: surgical connection between two hollow/tubular structures Ileectomy: surgical removal of the ileum Ostomy: surgical creation of an opening between organ and body surface (stoma) o Ileostomy: surgical creation of artificial opening between ileum and outside of abdominal wall o Colostomy: surgical creation of artificial opening between colon and body surface Hemorrhoidectomy: surgical removal of hemorrhoids (rubber band ligation = tying of blood vessels at base of hemorrhoid → falls off) Proctopexy: surgical fixation of prolapsed rectum to adjacent tissue/organ Hepatectomy: surgical removal of all/part of liver Liver transplant: liver inserted into patient with failed liver (no cancer) from donor Choledocholithotomy: surgical incision into common bile duct to remove a gallstone Cholecystectomy: surgical removal of gallbladder o Open cholecystectomy: incision in right upper abdomen o Laparoscopic cholecystectomy: surgical removal through 3-4 small incisions + laparoscope

Careers:

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Bariatrics: prevention/control of obesity and associated diseases Dentist: diagnosing + treating disorders of teeth and oral cavity tissues Gastroenterologist: diagnosing + treating diseases of the stomach and intestines Oral or maxillof...