Medical Terminology: The Gastrointestinal System

1. What is The Gastrointestinal System?
The gastrointestinal system includes the alimentary canal (mouth, esophagus, stomach, small intestine, large intestine, and rectum), accessory organs (salivary glands, liver, pancreas, and gallbladder), and ducts.
The alimentary canal is a hollow tube lined with mucous membrane. The gastrointestinal tract functions to digest food, absorb nutrients, propel the contents through the lumen, and eliminate the waste products. Digestion of food has both mechanical and chemical components. Both processes begin in the mouth. Chewing, movement through the gastrointestinal (GI) tract, and churning within the stomach are parts of the mechanical process. Saliva, hydrochloric acid, bile, and other digestive enzymes all contribute to the chemical process of digestion.
The esophagus extends from the oropharynx to the stomach. At the top of the esophagus is the upper esophageal sphincter (UES) to prevent the influx of air into the esophagus during respiration. At the bottom of the esophagus is the lower esophageal sphincter (LES) to prevent the reflux of acid from the stomach into the esophagus. The contents of the esophagus empty into the stomach through the cardiac sphincter. The stomach secretes gastrin, which promotes secretion of pepsinogen and hydrochloric acid, pepsin, and lipase, all of which aid digestion, and mucus formation, which helps protect the stomach lining.
The liver is a very vascular organ located in the right upper quadrant of the abdomen under the diaphragm. It has two main lobes that are comprised of smaller lobules. The liver stores a variety of vitamins and minerals. It metabolizes proteins; synthesizes plasma proteins, fatty acids, and triglycerides; and stores and releases glycogen.
The liver detoxifies foreign substances such as alcohol, drugs, or chemicals. The liver forms and secretes bile to aid in digestion of fat. Bile releases into the gallbladder for storage or into the duodenum if needed for digestion if the sphincter of Oddi is open because of secretion of the digestive enzymes secretin, cholecystokinin, and gastrin.
The gallbladder is a small receptacle that holds bile until it is needed. It is located on the inferior aspect of the liver. The pancreas is located retroperitoneally in the upper abdomen near the stomach and extends from just right of midline to the left toward the spleen.
The pancreas has both endocrine and exocrine functions. The endocrine functions include secretion of insulin in response to elevations in blood glucose from the beta cells of the islets of Langerhans and glucagon in response to decrease in blood glucose from the alpha cells. The exocrine function includes secretion of trypsin, lipase, amylase, and chymotrypsin to aid in digestion.
The small intestine is composed of the duodenum, jejunum, and ileum. The duodenum attaches to the stomach, is about 1. foot long and C-shaped, and curves to the left around the pancreas. The common bile duct and pancreatic duct enter here. The jejunum is between the duodenum and ileum and is about 8. feet long.
The last portion of the small intestine is the ileum, which is up to 12. feet long, depending on the size of the patient. The ileocecal valve separates the ileum from the large intestine. The appendix is found at this juncture.
The large intestine can be broken down into the ascending colon, transverse colon, descending colon, and sigmoid colon. The sigmoid colon joins the rectum and ultimately the anal canal.

2. Appendicitis
Inflammation of the vermiform appendix (a blind pouch located near the ileocecal valve in the right lower quadrant of the abdomen) is known as appendicitis. It may be caused by obstruction from stool.
The mucosal lining of the appendix continues to secrete fluid, which increases the pressure within the lumen of the appendix, causing a restriction of the blood supply to the appendix. This decrease in blood supply may result in gangrene or perforation as the pressure continues to build. Pain localizes at McBurney’s point, located midway between the umbilicus and right anterior iliac crest. Appendicitis may occur at any age, but the peak occurrence is from the teenage years to age 30.

3. Cholecystitis
An inflammation of the gallbladder, often accompanied by the formation of gallstones (cholelithiasis), is cholecystitis. The inflammation may be either acute or chronic in nature. In an acute cholecystitis, the blood flow to the gallbladder may become compromised, which in turn causes problems with the normal filling and emptying of the gallbladder. A stone may block the cystic duct, which results in bile becoming trapped within the gallbladder because of inflammation around the stone within the duct.
Blood flow to the inflamed area is minimized, localized edema develops, the gallbladder distends because of retained bile, and ischemic changes occur within the wall of the gallbladder. Chronic cholecystitis occurs when there have been recurrent episodes of blockage of the cystic duct, usually because of stones. There is chronic inflammation.
The gallbladder is often contracted, which leads to problems with storing and moving the bile. Patients may develop jaundice because of a backup of bile or obstructive jaundice. They exhibit a yellowish tone to skin and mucous membranes. If patients have a naturally dark pigmentation to their skin, the practitioner should check palms and soles.
Icterus is the yellow color change seen in the sclera (white) of the eye. There is increased risk for gallbladder inflammation and development of gallstones with increasing age, being female or overweight, having a family history, people on rapid weight loss diets, and during pregnancy.

4. Cirrhosis
Injury to the cellular structure of the liver causes fibrosis because of chronic inflammation and necrotic changes, resulting in cirrhosis. There are nodular changes to the liver. The bile ducts and blood vessels through the liver may become blocked because of both the nodular changes and fibrosis.
These changes to the liver cause enlargement of the organ and change in texture. There is increased pressure within the portal vein. This causes resistance to blood flow throughout the venous system in the liver and also backs up venous blood to the spleen, causing enlargement of this organ also.
Damage to the liver may be reversible if the cause is identified early and removed. The most common causes of cirrhosis include chronic alcohol use, liver damage secondary to exposure to drugs or toxins, viral hepatitis (especially hepatitis B, hepatitis C, and hepatitis D in those already infected with hepatitis B), fatty liver (steato-hepatitis), autoimmune hepatitis, cystic fibrosis, metabolic disorders (excess iron storage—hemochromatosis), or genetic causes.

5. Crohn’s Disease
Crohn’s disease is a noncontinuous inflammatory disease that can affect any point from the mouth to the anus. The majority of cases involve the small and large intestine, often in the right lower quadrant at the point where the terminal ileum and the ascending colon meet.
Patients typically have an insidious onset of intermittent symptoms. The disease causes transmural inflammation, going deeper than the superficial mucosal layer of the tissue to affect all layers. Over time the inflammatory changes within the GI tract can lead to strictures or the formation of fistulas. The affected tissue develops granulomas and takes on a mottled appearance interspersed with normal tissue. There is a genetic predisposition.

6. Diverticulitis
Small outpouchings called diverticula develop along the intestinal tract. Diverticulosis is the condition of having these diverticula. Any part of the large or small intestine may be involved. The area of the intestinal tract that most commonly develops diverticula is the lower portion of the large intestine. Certain types of undigested foods can become trapped in the pouches of the intestine.
Bacteria multiply in the area, causing further inflammation. Diverticulitis is an inflammation of at least one of the diverticula. Diets that have a low fiber content, seeds, or nuts have been implicated in the development of diverticulitis. Perforation of the diverticula is possible when they are inflamed.

7. Gastroenteritis
This is an acute inflammation of the gastric and intestinal mucosa that is most commonly caused by bacterial, viral, protozoal, or parasitic infection. It may also be caused by irritation due to chemical or toxin exposure or allergic response. Viral exposure is more likely in winter; bacterial exposure is more common in winter when foodborne illness exposure is likely.

8. Gastroesophageal Reflux Disease (GERD)
Gastroesophageal reflux disease (GERD) is the reflux of stomach acid and contents into the esophagus. This typically causes symptoms because the lining of the esophagus is not protected against the acid that is normally found only in the stomach. The pain that is produced is often referred to as heartburn, or may be mistaken for cardiac pain. The pain may also extend to the back.
The pain occurs more frequently in men, people who are obese, smokers, and those who use alcohol or medications that lower the muscle tone of the lower esophageal sphincter. The pain caused by acid refluxing into the esophagus is worse after eating or when lying down. Patients with a hiatal hernia may also experience reflux because of the increased pressure that exists from a portion of the stomach protruding upward through the diaphragm.

9. Gastrointestinal Bleeds
Bleeding from the GI tract may cause significant blood loss. The bleeding may be from either the upper or lower GI tract. Upper gastrointestinal bleeds are commonly from ulcers, esophageal varices, neoplasms, arteriovenous malformations, Mallory-Weiss tears secondary to vomiting, or anticoagulant use.
Lower gastrointestinal bleeds are commonly caused by fissure formation, rectal trauma, colitis, polyps, colon cancer, diverticulitis, vasculitis, or ulcerations.

10. Gastritis
Gastritis is an inflammation of the stomach lining resulting from either erosive or atrophic causes. Erosive causes include stresses such as physical illness or medications such as nonsteroidal anti-inflammatory drugs (NSAIDs). Atrophic causes include a history of prior surgery (such as gastrectomy), pernicious anemia, alcohol use, or Helicobacter pylori infection.

11. Hepatitis
Hepatitis is an inflammation of the liver cells. This most commonly results from a viral cause, which may be either an acute illness or become chronic. The disease may also be caused by exposure to drugs or toxins.
- Hepatitis A: Hepatitis A is transmitted via an oral route, often by contaminated water or poor sanitation when traveling; it is also transmitted in daycare settings and residential institutions. It can be prevented by vaccine.
- Hepatitis B: Hepatitis B is transmitted via a percutaneous route, often by sexual contact, IV drug use, mother-to-neonate transmission, or possibly blood transfusion. It can be prevented by vaccine.
- Hepatitis C: Hepatitis C is transmitted via a percutaneous route, often by IV drug use or, less commonly, sexual contact. There is currently no vaccine available.
- Hepatitis D: Hepatitis D is transmitted via a percutaneous route and needs hepatitis B to spread cell to cell. There is no vaccine available for hepatitis D.
- Hepatitis E: Hepatitis E is transmitted via an oral route and is associated with water contamination. There is no known chronic state of hepatitis E and no current vaccine available.
- Hepatitis G: Hepatitis G is transmitted via a percutaneous route and is associated with chronic infection but not significant liver disease.
Exposure to medications (even at therapeutic doses), drugs, or chemicals can also cause hepatitis. Onset is usually within the first couple of days of use, and may be within the first couple of doses. Hepatotoxic substances include acetaminophen, carbon tetrachloride, benzenes, and valproic acid.

12. Hiatal Hernia
This is also known as a diaphragmatic hernia. A part of the stomach protrudes up through the diaphragm near the esophagus into the chest. Patients may be asymptomatic or have daily symptoms of gastroesophageal reflux disease (GERD).
The hernia may be a sliding hiatal hernia, which allows movement of the upper portion of the stomach including the lower esophageal sphincter up and down through the diaphragm. These patients typically have symptoms of GERD.
Another type of hiatal hernia is a rolling hernia, in which a portion of the stomach protrudes up through the diaphragm, but the lower esophageal sphincter area remains below the level of the diaphragm. These patients do not generally suffer from reflux.

13. Intestinal Obstruction and Paralytic Ileus
An intestinal obstruction occurs when motility through the intestine is blocked. This may be caused by a mechanical obstruction due to the presence of a tumor, adhesions from prior surgery, or infection or fecal impaction.
A paralytic ileus results when motility through the intestine is blocked without any obstructing mass. This may occur during the postoperative period following intraabdominal surgery, during a severe systemic illness (sepsis), electrolyte imbalance, or because of a metabolic disorder (diabetic ketoacidosis).

14. Pancreatitis
Pancreatitis is an inflammation of the pancreas that causes destructive cellular changes. It may be an acute or a chronic process. Acute pancreatitis involves autodigestion of the pancreas by pancreatic enzymes and development of fibrosis. Blood glucose control may be affected by the changes to the pancreas.
Chronic pancreatitis results from recurrent episodes of exacerbation, leading to fibrosis and a decrease in pancreatic function. Presence of gallstones blocking a pancreatic duct, chronic use of alcohol, postabdominal trauma or surgery, or elevated cholesterol are associated with an increased risk of pancreatitis.

15. Peritonitis
Peritonitis is an acute inflammation of the peritoneum, which is the lining of the abdominal cavity. Peritonitis may be primary or secondary to another disease process. It typically occurs because of bacterial presence within the peritoneal space.
The bacteria may have passed from the GI tract or the rupture of an organ within the abdomen or pelvis. After the introduction of the bacteria into the abdominal area, an inflammatory reaction occurs.

16. Peptic Ulcer Disease (PUD)
An ulcer develops when there is erosion of a portion of the mucosal layer of either the stomach or duodenum. The ulcer may occur within the stomach (gastric ulcer) or the duodenum (duodenal ulcer). A break in the protective mucosal lining allows the acid within the stomach to make contact with the epithelial tissues. Gastric ulcers favor the lesser curvature of the stomach.
Duodenal ulcers tend to be deeper, penetrating through the mucosa to the muscular layer. H. pylori infection has been associated with duodenal ulcers. Stress ulcers are associated with another acute medical condition or traumatic injury.
As the body attempts to heal from the other physical condition (e.g., major surgery), small areas of ischemia develop within the stomach or duodenum. The ischemic areas then ulcerate.

17. Ulcerative Colitis
Ulcerative colitis is an inflammatory disease of the large intestine that affects the mucosal layer beginning in the rectum and colon and spreading into the adjacent tissue. There are ulcerations in the mucosal layer of the intestinal wall, and inflammation and abscess formation occur. Bloody diarrhea with mucus is the primary symptom.
There are periods of exacerbations and remissions. Symptom severity may vary from mild to severe. The exact cause is unknown, but there is increased incidence in people with northern European, North American, or Ashkenazi Jewish origins. The peak incidences are from mid-teens to mid-20s and again from mid-50s to mid-60s.

18. Gastroscopy
This test is used to diagnose peptic, gastric, or duodenal ulcers and obtain biopsies and specimens for H. pylori bacteria. An informed consent is obtained before any anesthesia. An endoscope is passed through the mouth to allow visualization of the pharynx, esophagus, lower esophageal sphincter, stomach, pyloric sphincter, and duodenum.
Biopsies can be obtained at this time. Bleeding, ulcers, lesions, and polyps can be visually assessed. The back of the throat will be anesthetized to allow passage of the endoscope.
Before the Test: The patient is NPO (nothing by mouth).
After the Test: The practitioner should monitor vital signs and assess for return of gag reflex. The patient remains NPO until the gag reflex returns.

19. Colonoscopy
This test is used to diagnose obstruction, bleeding, change in bowel habits, and colon cancer, among other conditions. An informed consent is obtained before the patient is given any type of anesthesia.
A colonoscope is passed through the rectum to visualize the anus, sigmoid, descending colon, splenic flex-ure, transverse colon, hepatic flexure, ascending colon, and the ileocecal valve. The colon may be insufflated to aid in visualization of the structures.
Biopsies are obtained as indicated. The scope is withdrawn and anesthesia is reversed. The patient may experience abdominal distention. Risks include perforation of the large intestine. The test is commonly performed as an outpatient procedure.
Before the Test: A thorough colon prep is necessary to ensure complete emptying of the bowel before the procedure. The patient is NPO for several hours before the test because of the use of an anesthetic agent.
After the Test: The practitioner should assess the abdomen for bowel sounds and tenderness. Monitor vital signs. Assess the patient for side effects of anesthesia.

20. Abdominal Ultrasound
This is a noninvasive test and is usually painless. A transducer is guided over the abdomen, which produces sound waves that bounce off internal structures and produce a picture of internal organs and structures.
Before the Test: The patient needs to be NPO.
After the Test: No special care is needed.

21. Liver Biopsy
Here, a small sample of tissue is removed from the liver and examined under a microscope, allowing for a definite diagnosis. A thin, cutting needle, through the skin of the abdomen, is used to obtain the sample. Needle biopsies are relatively simple procedures requiring only local anesthesia. Risks include bruising, bleeding, and infection.
Before the Test: Informed consent is needed.
After the Test: The practitioner should monitor vital signs for drop in blood pressure as well as an increase in pulse or respiration. The practitioner should check the site for bruising or bleeding, and check the skin for pallor or sweating.

22. Endoscopic Retrograde Cholangiopancreatography (ERCP)
Here, a thin, flexible tube (endoscope) is passed through the pharynx, the stomach, and into the upper part of the small intestine. Air is used to inflate the intestinal tract to enable the openings of the pancreatic and bile ducts to be seen. A dye is injected into the ducts through a catheter via the endoscope. X-rays are taken of the ducts. The patient may report abdominal distention from the insufflation and a sore throat.
Before the Test: The patient is NPO.
After the Test: The practitioner should monitor vital signs and assess for return of gag reflex. The patient remains NPO until gag reflex returns.

23. Liver Function Tests
These comprise several tests, obtained through a venipuncture, that show hepatic function. They generally include:
- Alanine Transaminase (ALT): An enzyme found mainly in liver cells, ALT helps the body metabolize protein. When the liver is damaged, ALT is released in the bloodstream.
- Aspartate Transaminase (AST): The enzyme AST plays a role in the metabolism of alanine, an amino acid. An increase in AST levels may indicate liver damage or disease.
- Alkaline Phosphatase (ALP): ALP is an enzyme found in high concentrations in the liver and bile ducts, as well as some other tissues. Higher-than-normal levels of ALP may indicate liver damage or disease.
- Albumin and Total Protein: Levels of albumin—a protein made by the liver—and total protein show how well the liver is making proteins that the body needs to fight infections and perform other functions. Lower-than-normal levels may indicate liver damage or disease.
- Bilirubin: Bilirubin is a red-yellow pigment that results from the breakdown of red blood cells. Normally, bilirubin passes through the liver and is excreted in stool. Elevated levels of bilirubin (jaundice) may indicate liver damage or disease.
- Gamma-Glutamyl Transferase (GGT): This test measures the amount of the enzyme GGT in the blood. Higher-than-normal levels may indicate liver or bile duct injury.
- Lactate Dehydrogenase (LDH): LDH is an enzyme found in many body tissues, including the liver. Elevated levels of LDH may indicate liver damage.
- Prothrombin Time (PT): This test measures the clotting time of plasma. Increased PT may indicate liver damage.
- Hepatitis Panel: Tests for acute viral hepatitis include HBsAg, anti-HAV, IgM anti-HBc, and anti-HCV. Tests for chronic hepatitis include HBsAg and anti-HCV. HAV is confirmed by detecting an IgM antibody to HAV (IgM anti-HAV); HBV by HBsAg and IgM anti-HBC (when HBeAg is detected, the patient is highly infectious); HCV by ELISA–2. and RIBA–2; HDV by anti-HDV and serologic markers for HBV. For HEV, only research-based tests are available at this time.

Basic Questions
Gastrointestinal System

1. What is appendicitis?
Inflammation of the vermiform appendix (a blind pouch located near the ileocecal valve in the right lower quadrant of the abdomen) is known as appendicitis.

2. What is McBurney’s point?
Pain from appendicitis localizes at McBurney’s point, located midway between the umbilicus and right anterior iliac crest.

3. What is cholecystitis?
Cholecystitis is inflammation of the gallbladder.

4. What is acute cholecystitis?
In an acute cholecystitis, the blood flow to the gallbladder may become compromised, which in turn causes problems with the normal filling and emptying of the gallbladder. A stone may block the cystic duct, which results in bile becoming trapped within the gallbladder because of inflammation around the stone within the duct.

5. What is icterus?
Icterus is the yellow color change seen in the sclera (white) of the eye.

6. What is cirrhosis?
Injury to the cellular structure of the liver causes fibrosis because of chronic inflammation and necrotic changes, resulting in cirrhosis.

7. What are the common causes of cirrhosis?
The most common causes of cirrhosis include chronic alcohol use, liver damage secondary to exposure to drugs or toxins, viral hepatitis (especially hepatitis B, hepatitis C, and hepatitis D in those already infected with hepatitis B), fatty liver (steatohepatitis), autoimmune hepatitis, cystic fibrosis, metabolic disorders (excess iron storage—hemochromatosis), or genetic causes.

8. What is Crohn’s disease?
Crohn’s disease is a noncontinuous inflammatory disease that can affect any point from the mouth to the anus. The majority of cases involve the small and large intestines, often in the right lower quadrant at the point where the terminal ileum and the ascending colon meet.

9. What is diverticulitis disease?
Small outpouchings called diverticula develop along the intestinal tract. Diverticulosis is the condition of having these diverticula. Any part of the large or small intestine may be involved.

10. What is gastroenteritis?
Gastroenteritis is an acute inflammation of the gastric and intestinal mucosa and is most commonly caused by bacterial, viral, protozoal, or parasitic infection.

11. What is gastroesophageal reflux disease (GERD)?
GERD is the reflux of stomach acid and contents into the esophagus. This typically causes symptoms, because the lining of the esophagus is not protected against the acid that is normally found only in the stomach. The pain that is produced is often referred to as heartburn, or may be mistaken for cardiac pain.

12. What is gastritis?
Gastritis is an inflammation of the stomach lining resulting from either erosive or atrophic causes.

13. What is hepatitis?
Hepatitis is an inflammation of the liver cells.

14. What is a hiatal hernia?
This is also known as a diaphragmatic hernia. A part of the stomach protrudes up through the diaphragm near the esophagus into the chest.

15. What is a paralytic ileus?
A paralytic ileus results when motility through the intestine is blocked without any obstructing mass.

16. What might cause a paralytic ileus?
This may occur during the postoperative period following intraabdominal surgery, during a severe systemic illness (sepsis), electrolyte imbalance, or because of a metabolic disorder (diabetic ketoacidosis).

17. What is pancreatitis?
Pancreatitis is an inflammation of the pancreas that causes destructive cellular changes.

18. What is acute pancreatitis?
Acute pancreatitis involves autodigestion of the pancreas by pancreatic enzymes and development of fibrosis.

19. What is chronic pancreatitis?
Chronic pancreatitis results from recurrent episodes of exacerbation, leading to fibrosis and a decrease in pancreatic function.

20. What is peritonitis?
Peritonitis is an acute inflammation of the peritoneum, which is the lining of the abdominal cavity.

21. What is peptic ulcer disease (PUD)?
An ulcer develops when there is erosion of a portion of the mucosal layer of either the stomach or duodenum.

22. What is ulcerative colitis?
Ulcerative colitis is an inflammatory disease of the large intestine that affects the mucosal layer beginning in the rectum and colon and spreading into the adjacent tissue. There are ulcerations in the mucosal layer of the intestinal wall, and inflammation and abscess formation occur.

23. What is a sliding hiatal hernia?
A sliding hiatal hernia allows movement of the upper portion of the stomach including the lower esophageal sphincter up and down through the diaphragm. These patients typically have symptoms of GERD.

24. What is a rolling hernia?
A rolling hernia is a type of hiatal hernia in which a portion of the stomach protrudes up through the diaphragm, but the lower esophageal sphincter area remains below the level of the diaphragm. These patients do not generally suffer from reflux.

25. What are duodenal ulcers?
Duodenal ulcers are peptic ulcers that tend to be deeper, penetrating through the mucosa to the muscular layer. H. pylori infection has been associated with duodenal ulcers.