Chapter 5 Digestive System

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3 functions of Digestive System 1. Digestion 2. Absorption 3. Elimination 1. Digestion 2. Absorption 3. Elimination

Digestive System Pharynx/throat- muscular tube lined with a mucous membrane and serves as a common passageway for air traveling to nasal cavity, trachea, and food going to the esophagus Epiglottis- flap in back of throat that covers trachea so food can’t enter trachea Pharynx/throat- muscular tube lined with a mucous membrane and serves as a common passageway for air traveling to nasal cavity, trachea, and food going to the esophagus Epiglottis- flap in back of throat that covers trachea so food can’t enter trachea

Digestive System Esophagus- eso=inward, phag/o=to swallow; it is a 9”-10” tube that extends from pharynx to stomach. **Rhythmic contractions of muscles propels food towards the stomach –Peristalsis- peri=surrounding, -stalsis=contraction: is the involuntary contraction of the esophagus Ileus- failure of peristalsis Achalasia= (-chalasia= relaxation); failure of the lower esophagus sphincter to relax so food cannot pass Dysphagia- (dys=bad; phagia=eat or swallow); difficulty in swallowing/eating Esophagus- eso=inward, phag/o=to swallow; it is a 9”-10” tube that extends from pharynx to stomach. **Rhythmic contractions of muscles propels food towards the stomach –Peristalsis- peri=surrounding, -stalsis=contraction: is the involuntary contraction of the esophagus Ileus- failure of peristalsis Achalasia= (-chalasia= relaxation); failure of the lower esophagus sphincter to relax so food cannot pass Dysphagia- (dys=bad; phagia=eat or swallow); difficulty in swallowing/eating

Digestive System Bolus- semisolid food going through esophagus into upper portion of stomach called the fundus. Food then goes to the body of the stomach or the middle section, and then the lower portion called the antrum. Sphincter- muscle rings controlling the openings into and out of the stomach: Pyloric sphincter- ring at distal end of stomach that allows food to leave stomach. Cardiac sphincter- ring at superior portion of stomach- relaxes and contracts food from esophagus into the stomach. Bolus- semisolid food going through esophagus into upper portion of stomach called the fundus. Food then goes to the body of the stomach or the middle section, and then the lower portion called the antrum. Sphincter- muscle rings controlling the openings into and out of the stomach: Pyloric sphincter- ring at distal end of stomach that allows food to leave stomach. Cardiac sphincter- ring at superior portion of stomach- relaxes and contracts food from esophagus into the stomach.

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Stomach *Mucous lines the stomach in folds called rugae which contains digestive glands that produce pepsin enzymes and hydrochloric acid. This begins the process of digestion. Food digests in about 1-4 hours where it is chemically and mechanically prepared for the sm intestine to digest and absorb into the blood stream.

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Small Intestine Small Intestine (3 parts)- millions of tiny villi line walls of sm intestines; these tiny villi absorb the digested nutrients into the bloodstream and lymph vessels – Duodenum- receives food from the stomach as well as bile from the liver, gall bladder, and pancreas –Jejunum –Ileum (leads to the lg intestines) Small Intestine (3 parts)- millions of tiny villi line walls of sm intestines; these tiny villi absorb the digested nutrients into the bloodstream and lymph vessels – Duodenum- receives food from the stomach as well as bile from the liver, gall bladder, and pancreas –Jejunum –Ileum (leads to the lg intestines)

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Large Intestines Large Intestines (6 parts): goes from the end of ileum to anus; receives waste products of digestion (not able to be absorbed into bloodstream) and then stores them until they are released as feces/defecation. Cecum- pouch on rt side and connects to ileum (appendix hangs from the cecum) Ascending colon- going from cecum to liver; it then turns left and becomes: Transverse colon- then passes horizontally towards spleen and becomes: Descending colon Sigmoid colon- “s” shaped; lies at distal end and leads to the Rectum- (then goes to the anus) Large Intestines (6 parts): goes from the end of ileum to anus; receives waste products of digestion (not able to be absorbed into bloodstream) and then stores them until they are released as feces/defecation. Cecum- pouch on rt side and connects to ileum (appendix hangs from the cecum) Ascending colon- going from cecum to liver; it then turns left and becomes: Transverse colon- then passes horizontally towards spleen and becomes: Descending colon Sigmoid colon- “s” shaped; lies at distal end and leads to the Rectum- (then goes to the anus)

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Pathway of food thru GI track Oral cavity Pharynx Esophagus Stomach Duodenum Jejunum Ileum Cecum Ascending Colon Transverse Colon Descending Colon Sigmoid Colon Rectum Anus Oral cavity Pharynx Esophagus Stomach Duodenum Jejunum Ileum Cecum Ascending Colon Transverse Colon Descending Colon Sigmoid Colon Rectum Anus

Accessory organs of Digestion: Liver (hepat/o)- manufactures bile which contains cholesterol, acids, and pigments such as bilirubin; regulates glucose in blood and stores it as glycogen. (Cirrohosis is liver disease resulting from alcoholism and malnutrition); bile leaves the liver via the hepatic duct which goes to the cystic duct leading to the gallbladder Gallbladder (cholecyst/o)- contracts to force out bile to the cystic duct into the common bile duct (which carries bile into the duodenum) Pancreas (pancreat/o)- secretes enzymes and the hormone insulin that travel through the pancreatic duct to duodenum. It is here that bile breaks apart large fat globules which is called emulsification. Without bile, most fat would be undigested. The pancreas produces enzymes to digest starch called amylase. Lipase digests fats; pepcin digests proteins. Liver (hepat/o)- manufactures bile which contains cholesterol, acids, and pigments such as bilirubin; regulates glucose in blood and stores it as glycogen. (Cirrohosis is liver disease resulting from alcoholism and malnutrition); bile leaves the liver via the hepatic duct which goes to the cystic duct leading to the gallbladder Gallbladder (cholecyst/o)- contracts to force out bile to the cystic duct into the common bile duct (which carries bile into the duodenum) Pancreas (pancreat/o)- secretes enzymes and the hormone insulin that travel through the pancreatic duct to duodenum. It is here that bile breaks apart large fat globules which is called emulsification. Without bile, most fat would be undigested. The pancreas produces enzymes to digest starch called amylase. Lipase digests fats; pepcin digests proteins.

Ducts Hepatic duct- takes bile from the liver and travels to the cystic duct Cystic duct- leads to/from gallbladder *After food is in the stomach the gallbladder contracts forcing bile from the cystic duct into the common bile duct; meanwhile the pancreas secretes enzymes into the pancreatic duct Common Bile duct- carries bile from liver and gallbladder to the duodenum Hepatic duct- takes bile from the liver and travels to the cystic duct Cystic duct- leads to/from gallbladder *After food is in the stomach the gallbladder contracts forcing bile from the cystic duct into the common bile duct; meanwhile the pancreas secretes enzymes into the pancreatic duct Common Bile duct- carries bile from liver and gallbladder to the duodenum

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Terms and Procedures Crohn’s Disease- Chronic inflammation of the intestinal tract; IBD (inflammatory bowel disease) *Cholelithiasis- gallstones *Ascites- abnormal accumulation of fluid in abdomen Hepatitis A- viral; spread by contaminated food or water; complete recovery Hepatitis B- viral; transmitted by blood transfusion, sexual contact, or use of contaminated needles; severe infection can cause destruction of liver cells, cirrhosis, or death. *A vaccine is provided for healthcare workers Hepatitis C- viral; transmitted by blood transfusions or needle inoculations and may cause chronic hepatitis Hemorrhoids- swollen, twisted, varicose veins in the rectal region Crohn’s Disease- Chronic inflammation of the intestinal tract; IBD (inflammatory bowel disease) *Cholelithiasis- gallstones *Ascites- abnormal accumulation of fluid in abdomen Hepatitis A- viral; spread by contaminated food or water; complete recovery Hepatitis B- viral; transmitted by blood transfusion, sexual contact, or use of contaminated needles; severe infection can cause destruction of liver cells, cirrhosis, or death. *A vaccine is provided for healthcare workers Hepatitis C- viral; transmitted by blood transfusions or needle inoculations and may cause chronic hepatitis Hemorrhoids- swollen, twisted, varicose veins in the rectal region

Terms and Procedures Ulcerative Colitis- chronic inflammation of the colon with presence of ulcers; chronic, idiopathic recurrent diarrheal disease Peritonitis- inflammation of the peritonium IBS- Irritable Bowel Syndrome; group of gastrointestinal symptoms associated with stress and tension Stool Guaiac or Hemoccult- test for blood in feces Barium Swallow- upper GI; x-ray images of the esophagus, stomach, and small intestine obtained after administering barium by the mouth Barium Enema- lower GI; x-ray images of the colon and rectum obtained after injection of barium into the rectum Oral leukoplakia- white plaques or patches on the mucosa of the mouth Ulcerative Colitis- chronic inflammation of the colon with presence of ulcers; chronic, idiopathic recurrent diarrheal disease Peritonitis- inflammation of the peritonium IBS- Irritable Bowel Syndrome; group of gastrointestinal symptoms associated with stress and tension Stool Guaiac or Hemoccult- test for blood in feces Barium Swallow- upper GI; x-ray images of the esophagus, stomach, and small intestine obtained after administering barium by the mouth Barium Enema- lower GI; x-ray images of the colon and rectum obtained after injection of barium into the rectum Oral leukoplakia- white plaques or patches on the mucosa of the mouth

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Copyright © 2001 by W. B. Saunders Company. All rights reserved. A) Three types of anastomoses= surgical opening b/w organs in body B) Mesentery= membrane in the middle of intestines holding together Fig. 5-15AB. Forward Back MENU

Copyright © 2001 by W. B. Saunders Company. All rights reserved. (From Lewis SM, Collier IC, Heitkemper MM: Medical-Surgical Nursing, 4th edition, St. Louis, Mosby, 1996, page 1274.) Ascites=abnormal accumulation of fluid in abdomen when fluid seeps out of bloodstream and collects in peritoneal cavity Fig Forward Back MENU

Copyright © 2001 by W. B. Saunders Company. All rights reserved. (Part B from DAmjanov I: Pathology for the Health-Related Professions, Philadelphia, WB Saunders, 1996, page 281.) A)Anal fistula and two types of polyps B)Multiple polyps of the colon (polyposis) Fig. 5-18AB. Forward Back MENU

Copyright © 2001 by W. B. Saunders Company. All rights reserved. A)Diverticula=abnormal side pockets in intestinal wall traps bacteria B) Esophageal varices= swollen tortuous vein Fig. 5-20AB. (Part B from DAmjanov I: Pathology for the Health-Related Professions, Philadelphia, WB Saunders, 1996, page 261.) AB Forward Back MENU

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Copyright © 2001 by W. B. Saunders Company. All rights reserved. A) Liver with alcoholic cirrhosis B) Cholesterol Gallstones Fig. 5-23AB. AB (Part A from Damjanov I: Pathology for the Health-Related Professions, Philadelphia, WB Saunders, 1996, page 301; Part B from Kumar V, Cotran RS, and Robbins S: Basic Pathology, 6th ed., Philadelphia, WB Saunders, 1997, page 551.) Forward Back MENU