The digestive system IThe digestive system Digestion n

The digestive system

I-The digestive system

Digestion n Digestion is the mechanical and chemical breaking down of food into smaller components that can be absorbed into a blood stream n Digestion is a form of catabolism: a break-down of larger food molecules to smaller ones.

Digestive system n In mammals, food enters the mouth, being chewed by teeth, with chemical processing beginning with chemicals in the saliva from the salivary glands. n Then it travels down the esophagus into the stomach, where hydrochloric acid kills most contaminating microorganisms and begins mechanical break down of some food (e. g. , denaturation of protein), and chemical alteration of some. n After some time (typically an hour or two in humans, the results go through the small intestine, through the large intestine, and are excreted during defecation.

other terms Lith/o Stone Lapar/o Abdominal wall Iasis (-osis) Abnormal condition Emes/o Emesis Vomit Melan/o Black pigment Scopy Technique of veiwing Rraphy Suture Ectasis Dialation - pepsia Digestion Phagia Eating/Swallowing Atresia no opening -ptosis drooping /sagging

-stomy n This means a mouth or opening. Usually a stoma is formed by surgery n e. g. a colostomy is an opening or the formation of an opening into the colon. n This word component is also used in anastomosis, an operation to form an opening/communication between two parts. n A stoma can be temporary or permanent. -tomy n Means an incision as at the beginning of an operation .

Related terms Gast/ritis inflammation of stomach Gastr/o/enteritis Inflammation of the stomach and intestine Gastr/ectomy Excision of stomach Hepat/itis inflammation of liver Hepat/oma tumor of liver Laparo/tomy cutting into the abdomen Laparo/scopy visual exam of the abdomen

Related terms Chole/litho/tomy removal of gall stones Chole/lith/iasis gall stones causing symptoms Chole/cystitis inflammation of gallbladder Chole/cystectomy removal of gallbladder Emetic stimulating vomiting Anti/emetic stopping vomiting

Related terms n Lymph/angi/ectasis Dialation of a lymph vessel n Dys/pepsia Difficult digestion n Dys/phagia Difficulty in swallowing n Splen/o/rrhagia Bursting forth of blood from the spleen n Sialo/lithiasis Salivary stones n Hemat/emesis Vomiting of blood

Clinical Aspects of Digestion

INFECTION n A variety of organisms can infect the gastrointestinal tract, from viruses and bacteria to protozoa and worms. n Some produce short-lived upsets with gastroenteritis, nausea, diarrhea, and emesis (vomiting). n Others, such as typhoid, cholera, and dysentery, are more serious, even fatal.

ULCERS n An ulcer is a lesion of the skin or a mucous membrane marked by inflammation and tissue damage. n Ulcers caused by the damaging action of gastric, or peptic, juices on the lining of the GI tract are termed peptic ulcers. n Most peptic ulcers appear in the first portion of the duodenum. n The origins of such ulcers are not completely known, although infection with a bacterium, Helicobacter pylori, has been identified as a major cause.

CANCER n The most common sites for cancer of the GI tract are the colon and rectum.

APPENDICITIS n Appendicitis results from infection of the appendix, often secondary to its obstruction. Surgery is necessary to avoid rupture and peritonitis, infection of the peritoneal cavity.

INFLAMMATORY BOWEL DISEASE n Two similar diseases are included under the heading of inflammatory bowel disease (IBD): n Crohn disease and ulcerative colitis, both of which occur mainly in adolescents and young adults. n Crohn disease is a chronic inflammation of segments of the intestinal wall, usually in the ileum, causing pain, diarrhea, abscess, and often formation of an abnormal passageway, or fistula. n Ulcerative colitis involves a continuous inflammation of the lining of the colon and usually the rectum.

PANCREATITIS n Pancreatitis, or inflammation of the pancreas, may result from alcohol abuse, drug toxicity, bile obstruction, infections, and other causes. n Blood tests in acute pancreatitis show increased levels of the enzymes amylase and lipase.

GALLSTONES n Cholelithiasis refers to the presence of stones in the gallbladder or bile n n n ducts, which is usually associated with cholecystitis, inflammation of the gallbladder. Most of these stones are composed of cholesterol, an ingredient of bile. Gallstones form more commonly in women than in men, especially in women on oral contraceptives and in those who have had several pregnancies. The condition is characterized by biliary colic (pain) in the right upper quadrant (RUQ), nausea, and vomiting. Drugs may be used to dissolve gallstones, but often the cure is removal of the gallbladder in a cholecystectomy. This procedure was originally performed through a major abdominal incision, but now the gallbladder is almost always removed laparoscopically through a small incision in the abdomen. Ultrasonography and radiography are used for diagnosis of gallstones.

HEPATITIS n Hepatitis is a disease that includes any type of inflammation of the liver, the result of a complex process that occurs when the liver suffers an injury. n Doctors call the inflammation that lasts less than six months acute hepatitis and inflammation that lasts longer than six months chronic hepatitis. n While there are many causes of liver inflammation, clinicians divide them into two main categories: viral hepatitis and non-infectious hepatitis

viral hepatitis n When most people think of hepatitis, they're usually thinking about viral hepatitis. n There are five viruses that commonly infect the liver, named using letters of the alphabet -- A through E. What makes viral hepatitis confusing is that each one of these viruses causes a slightly different type of disease and has a different way of spreading. n Some of these viral infections can result in acute, chronic or both forms of hepatitis. n Since these viruses spread from person to person, doctors also call this type of hepatitis infectious hepatitis.

Non-Infectious Hepatitis n Chemicals such as alcohol or medications can be harmful to the liver and can cause inflammation. n In addition, other health problems like genetic and metabolic disorders, immune-related injury and obesity, can damage the liver and lead to inflammation. n Since these types of hepatitis cannot spread from one person to another, clinicians call it non-infectious hepatitis.

CIRRHOSIS n Cirrhosis is a chronic liver disease characterized by hepatomegaly, edema, ascites, and jaundice. n As the disease progresses there is splenomegaly, internal bleeding, and brain damage caused by changes in the composition of the blood. n A complication of cirrhosis is increased pressure in the portal system that brings blood from the abdominal organs to the liver, a condition called portal hypertension. n The main cause of cirrhosis is the excess consumption of alcohol.

n Bilirubin A pigment released in the breakdown of hemoglobin from red blood cells; mainly excreted by the liver in bile n Icterus n n Jaundice n A yellowish color of the skin, mucous membranes, and whites of the eye caused by bile pigments in the blood (from French jaune meaning“yellow”). The main pigment is bilirubin.

Other conditions n Esophageal atresia no opening of the esophaagus at birth n Cecostomy new opening of the first part of the colon to the outside n Jejunoje/junostomy New opening between two parts of the jejunum n Pyloric Stenosis Narrowing of the opening between the stomach and intestine

n Colic n Acute abdominal pain, such as biliary colic caused by gallstones in the bile ducts Paracentesis n Collection of peritoneal fluid n Anorexia n Loss of appetite. Anorexia nervosa is a psychologically induced refusal or inability to eat n Constipation n Infrequency or difficulty in defecation and the passage of hard, dry feces.

Endoscopy Use of a fiberoptic endoscope for direct visual examination. GI studies include n Esophagogastroduodenoscopy n Proctosigmoidoscopy (rectum and distal colon) n Colonoscopy (all regions of the colon) n Gastroscopy (stomach) Gastroscopy

Liver Function Tests • The routine liver function tests include the measurement of : 1. Total , direct and indirect bilirubin 2. Total proteins and albumin 3. Liver enzymes include : ALT ( Alanine transaminase ) AST ( Aspartate transaminase ) Al. P ( Alkaline phosphatase ) 1. GGT ( - Glutamyl transferase )