Gastrointestinal Power Hour Vocabulary

Flashcards covering the anatomy, motility, hormones, and common pathologies of the gastrointestinal system, liver, and biliary tract.

GI tract

A continuous tube extending from the mouth to the anus with a layered structure influenced by the enteric nervous system, autonomic nervous system, hormones, and immune cells.

Salivary glands

Accessory organs that produce saliva to lubricate food and begin the digestion of starch and fat.

Liver

An accessory organ that produces bile for fat digestion.

Pancreas

An accessory organ that produces bicarbonate-rich fluid to neutralize stomach acid and digestive proenzymes activated in the small intestine.

Peristalsis

A type of GI motility that moves contents through the digestive tract.

Segmentation

A type of GI motility that mixes GI contents to aid digestion.

Enteric Nervous System (ENS)

A system that operates independently to control GI motility and secretions.

Parasympathetic nervous system

A division of the autonomic nervous system originating from the brainstem (vagus nerve) and sacral cord that stimulates GI motility and secretion.

Sympathetic nervous system

A division of the autonomic nervous system originating from the thoracic spinal cord that generally inhibits GI activity.

Gastrin

A hormone secreted by G cells in the stomach antrum that stimulates gastric acid secretion.

Cholecystokinin (CCK)

A hormone secreted by I cells in the proximal small intestine that stimulates gallbladder contraction and pancreatic enzyme secretion while inhibiting gastric emptying.

GLP-1

A hormone secreted by L cells in the distal small intestine that stimulates insulin secretion, inhibits gastric emptying, and signals satiety.

Histamine

A substance released from enterochromaffin cells in the stomach that stimulates gastric acid secretion.

Serotonin

A substance secreted from enterochromaffin cells in the small intestine that increases gastric motility.

Peyer's patches

Hubs of gut immune activity located in the small intestine that provide protection against ingested pathogens.

Gut microbiome

The collection of gut bacteria that outnumber human cells and perform functions such as producing Vitamin K and short-chain fatty acids.

Helicobacter pylori

A bacterial infection that serves as one of the two main causes of peptic ulcer disease.

Zollinger-Ellison syndrome

A condition identified as one of the two main causes of peptic ulcer disease.

Crypts and villi

Structures in the small intestine that increase the surface area available for absorption.

Microvilli

Projections on intestinal epithelial cells (IECs) that further increase the absorptive surface area.

Tight junctions

Structures between cells that prevent toxins and pathogens from entering the circulation.

Systemic inflammatory response syndrome (SIRS)

A potential complication of acute pancreatitis that involves widespread inflammation and can lead to multiorgan dysfunction.

Celiac disease

An immune-mediated disease where gluten ingestion leads to the formation of antigenic gliadin peptides and destruction of intestinal villi.

Haustral contractions

Slow movements in the large intestine that mix contents.

Mass movements

Movements in the large intestine that propel contents toward the rectum.

Crohn Disease

An inflammatory bowel disease characterized by transmural, discontinuous lesions that can occur anywhere from the mouth to the rectum.

Ulcerative Colitis

An inflammatory bowel disease limited to the colon involving the mucosa and submucosa, often resulting in greater blood loss.

Portal vein

A vessel supplying $75-80\%$ of liver blood flow, carrying nutrient-rich blood from the stomach, intestines, pancreas, and spleen.

Hepatic artery

The primary source of oxygen for the liver, supplying oxygenated blood.

Sphincter of Oddi

The valve that controls the flow of bile and pancreatic secretions into the duodenum.

Micelles

Structures formed by bile acids that carry lipid digestion products to the intestinal brush border for absorption.

Glycogenesis

The process occurring in the fed state where glucose is stored as glycogen in the liver.

Glycogenolysis

The breakdown of glycogen to produce glucose during the fasting state.

Gluconeogenesis

The production of new glucose by the liver during fasting.

Unconjugated (indirect) bilirubin

A hydrophobic and nonpolar form of bilirubin that travels in the bloodstream bound to albumin.

Conjugated (direct) bilirubin

A water-soluble form of bilirubin that is conjugated with glucuronic acid in the liver and secreted into bile.

Stercobilin

A pigment derived from bilirubin that gives feces their brown color.

Cholestasis

A condition associated with pale stools due to the impairment of bile flow or bilirubin excretion.

Cytochrome P450 enzymes

Enzymes in the liver's smooth ER that metabolize drugs by adding reactive chemical handles.

Hepatitis A (HAV)

An acute RNA virus transmitted through the fecal-oral route.

Hepatitis B (HBV)

A DNA virus transmitted via blood that can cause both acute and chronic infections.

Hepatitis C (HCV)

An RNA virus transmitted via blood that can cause both acute and chronic infections.