Gastrointestinal System: Anatomy, Physiology, Pathology, and Pharmacology

Comprehensive vocabulary flashcards covering gastrointestinal embryology, anatomy, physiology, pathology, and pharmacology based on the Dr. Mohammed Aljunaid AAU-Batch19 lecture transcript.

Foregut

The embryonic gut region extending from the esophagus to the duodenum at the level of the pancreatic duct and common bile duct insertion (ampulla of Vater).

Midgut

The embryonic gut region extending from the lower duodenum to the proximal $\frac{2}{3}$ of the transverse colon; it undergoes physiologic herniation through the umbilical ring during the $6^{th}$ week of development.

Hindgut

The embryonic gut region extending from the distal $\frac{1}{3}$ of the transverse colon to the anal canal above the pectinate line.

Gastroschisis

The extrusion of abdominal contents through abdominal folds, typically to the right of the umbilicus, with no covering membrane.

Omphalocele

A midline herniation of abdominal contents into the umbilical cord through the umbilical ring, covered by a sac containing multiple organs.

Esophageal Atresia with Distal Fistula

The most common type of tracheoesophageal fistula account for approximately $85\%$ of cases, presenting with drooling, choking, and air in the stomach.

Infantile Hypertrophic Pyloric Stenosis

A condition presenting in first-born boys with projectile nonbilious emesis and an "olive-shaped" abdominal mass, often leading to hypochloremic metabolic alkalosis.

Duodenal Atresia

A failure of recanalization at $8$ to $10$ weeks gestation, frequently associated with Down syndrome and the "double bubble sign" on x-ray.

Annular Pancreas

An abnormal rotation of the ventral pancreatic bud that encircles the duodenum, potentially causing narrowing.

Retroperitoneal Organs (SAD PUCKER)

Includes Suprarenal glands, Aorta/IVC, Duodenum (except $1^{st}$ part), Pancreas (head and body), Ureters, Colon (ascending/descending), Kidneys, Esophagus, and Rectum (mid-distal).

Pringle Maneuver

The manual compression of the hepatoduodenal ligament to control bleeding from the hepatic artery or portal vein.

Parietal Cells

Cells in the stomach that secrete Gastric Acid ($HCl$) and Intrinsic Factor.

Chief Cells

Cells located in the deeper aspect of gastric glands that secrete pepsinogen, which is converted to pepsin in the presence of $H^+$.

Brunner Glands

$HCO_3^-$ secreting cells located in the submucosa of the duodenum to neutralize gastric acid.

Peyer Patches

Unencapsulated lymphoid tissue in the lamina propria and submucosa of the ileum that contain M cells and facilitate $IgA$ secretion.

Watershed Zones of the Colon

Areas susceptible to ischemia including the splenic flexure (SMA and IMA) and the rectosigmoid junction (IMA and superior rectal artery).

SMA Syndrome

Compression of the third (transverse) portion of the duodenum between the superior mesenteric artery and the aorta, often due to low body weight.

Nutcracker Syndrome

Compression of the left renal vein between the superior mesenteric artery and the aorta, resulting in flank pain and hematuria.

Cholecystokinin (CCK)

Produced by I cells in the duodenum and jejunum; it increases pancreatic secretion and gallbladder contraction while slowing gastric emptying.

Secretin

Produced by S cells in the duodenum; it increases pancreatic $HCO_3^-$ secretion and decreases gastric acid secretion.

Vasoactive Intestinal Polypeptide (VIP)

Increases intestinal water and electrolyte secretion and relaxes intestinal smooth muscle and sphincters; excess levels cause WDHA syndrome.

D-xylose Test

A test used to distinguish between gastrointestinal mucosal damage (e.g., Celiac disease) and pancreatic insufficiency; it requires intact mucosa for absorption.

Achalasia

The failure of the lower esophageal sphincter (LES) to relax due to loss of the myenteric (Auerbach) plexus, characterized by a "bird's beak" sign on barium swallow.

Mallory-Weiss Tear

A mucosal tear at the gastroesophageal junction caused by forceful retching, leading to hematemesis; often associated with alcoholism or hiatal hernia.

Boerhaave Syndrome

A transmural esophageal rupture due to violent retching, often leading to pneumomediastinum and subcutaneous emphysema.

Barrett Esophagus

Specialized intestinal metaplasia in the distal esophagus where nonkeratinized stratified squamous epithelium is replaced by nonciliated columnar epithelium with goblet cells.

Menetrier Disease

Hyperplasia of gastric mucosa leading to hypertrophied rugae that resemble brain gyri, causing protein loss and parietal cell atrophy.

Krukenberg Tumor

Bilateral metastases to the ovaries from gastric adenocarcinoma, characterized by signet-ring cells.

Celiac Disease

An autoimmune-mediated intolerance of gliadin causing villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis in the duodenum.

Whipple Disease

Infection with Tropheryma whipplei characterized by PAS-positive foamy macrophages in the intestinal lamina propria.

Crohn Disease

Inflammatory bowel disease that can occur anywhere from mouth to anus, featuring skip lesions, transmural inflammation, and noncaseating granulomas.

Ulcerative Colitis

Inflammatory bowel disease always involving the rectum and extending proximally into the colon, featuring mucosal/submucosal inflammation and crypt abscesses.

Meckel Diverticulum

A true diverticulum resulting from a persistent vitelline duct, located within $2$ feet of the ileocecal valve.

Hirschsprung Disease

A congenital failure of neural crest cell migration to the rectosigmoid colon, resulting in an aganglionic segment and a transition zone on contrast enema.

Intussusception

The telescoping of a proximal bowel segment into a distal segment, presenting with episodic pain and "currant jelly" stools.

Volvulus

The twisting of a portion of the bowel around its mesentery; sigmoid volvulus often shows a "coffee bean" sign on x-ray.

Familial Adenomatous Polyposis (FAP)

An autosomal dominant mutation of the APC gene on chromosome $5q22$ that leads to $100\%$ colon cancer risk.

Wilson Disease

An autosomal recessive mutation of ATP7B causing hepatic copper accumulation and deposition in the basal ganglia and cornea (Kayser-Fleischer rings).

Hemochromatosis

A condition of iron overload, often due to HFE gene mutations, leading to the triad of cirrhosis, diabetes mellitus, and skin hyperpigmentation (bronze diabetes).

Charcot Triad

A clinical presentation of acute cholangitis consisting of fever, jaundice, and right upper quadrant (RUQ) pain.