Digestive System – Accessory Organs & Large Intestine Vocabulary

Comprehensive vocabulary set covering key organs, structures, processes, and clinical terms related to the pancreas, liver, gallbladder, and large intestine from Digestion Module 3 lecture.

Pancreas

Accessory gland that secretes digestive enzymes and bicarbonate‐rich pancreatic juice into the duodenum; also performs endocrine sugar regulation.

Pancreatic duct

Tube running through the pancreas that delivers pancreatic juice to the duodenum.

Pancreatic juice

Alkaline mixture of buffers (bicarbonate) and digestive enzymes released from the pancreas.

Bicarbonate

Buffer in pancreatic juice that neutralizes acidic chyme entering the duodenum.

Amylase

Pancreatic enzyme that digests carbohydrates (starches) into sugars.

Protease

Pancreatic enzyme family that breaks proteins into peptides and amino acids.

Lipase

Pancreatic enzyme that hydrolyzes dietary fats after they are emulsified by bile.

Liver

Large metabolic organ with 200+ functions, including bile production, blood detoxification, nutrient metabolism, and vitamin storage.

Hepatocyte

Functional liver cell responsible for metabolism and bile secretion.

Hepatic portal vein

Vein that carries nutrient-rich blood from the small intestine directly to the liver for processing.

Hepatic portal system

Vascular network that routes intestinal blood through liver sinusoids before it reaches the inferior vena cava.

Sinusoid

Leaky capillary channel within a liver lobule where blood from the hepatic portal system percolates.

Lobule

Hexagonal structural unit of the liver composed of hepatocytes surrounding a central vein.

Falciform ligament

Peritoneal ligament separating the liver’s right and left lobes and anchoring it to the anterior abdominal wall.

Gallbladder

Muscular sac beneath the liver that stores and concentrates bile until it is needed in the duodenum.

Bile

Liver-made greenish fluid containing bile salts that emulsify fats in the small intestine.

Emulsification

Process by which bile salts break large fat droplets into tiny micelles, increasing surface area for lipase.

Common bile duct

Duct formed by the union of the hepatic and cystic ducts, carrying bile to the duodenum.

Hepatitis

Inflammation of the liver, commonly viral (types A-G) or alcohol-induced.

Cirrhosis

Irreversible liver scarring and loss of function resulting from chronic inflammation such as hepatitis or alcoholism.

Cholecystitis

Inflammation of the gallbladder, often due to obstruction by gallstones.

Gallstone

Solid deposit (usually cholesterol or pigment) that can block the cystic or common bile duct and cause pain.

Bile salts

Recycled components of bile reabsorbed in the large intestine and returned to the liver to make new bile.

Glycogen

Branched polysaccharide stored in the liver; synthesized or broken down to regulate blood glucose.

Calcitriol

Active vitamin D hormone produced after the liver converts vitamin D₃ into an intermediate for the kidney.

Cecum

Blind pouch at the start of the large intestine that receives chyme from the ileum; hosts the appendix.

Appendix

Narrow, worm-like extension of the cecum thought to help reseed gut flora.

Ascending colon

First vertical segment of the large intestine that carries fecal matter upward on the right side.

Transverse colon

Horizontal segment of the large intestine crossing the abdominal cavity.

Descending colon

Section of the large intestine that travels downward on the left side toward the sigmoid colon.

Sigmoid colon

S-shaped terminal portion of the colon leading into the rectum.

Haustra

Pouch-like sacculations of the large intestine wall that permit expansion and elongation.

Tinea coli

Longitudinal band of smooth muscle running along the large intestine, giving rise to haustra.

Internal anal sphincter

Involuntary smooth-muscle ring that helps maintain fecal continence.

External anal sphincter

Voluntary skeletal-muscle ring learned during potty training to control defecation.

Hemorrhoid

Dilated or ruptured vein in the anal canal that may bleed and cause pain.

Diverticulosis

Condition of having small mucosal outpouchings (diverticula) in the large intestine wall.

Diverticulitis

Inflammation or infection of diverticula, leading to abdominal pain and possible bleeding.

Intestinal microbiota

Community of ~10¹⁴ microbial cells from thousands of species inhabiting the gut, outnumbering host cells.

Quorum sensing

Chemical communication method microbes use to gauge population density and coordinate behavior.

Probiotic

Live microbial supplement (e.g., in yogurt) intended to confer health benefits by enhancing gut flora.

Mutualism

Symbiotic relationship in which both host and microbe benefit (e.g., vitamin synthesis by gut bacteria).

Commensalism

Symbiosis where a microbe benefits and the host is presumed unaffected.

Parasitism

Symbiosis in which the microbe benefits at the host’s expense, causing harm (e.g., C. difficile infection).

Peristalsis

Wavelike muscular contractions that propel contents through the digestive tract.

Defecation reflex

Neural reflex triggered by rectal distension that initiates elimination of feces.