The Digestive System - Vocabulary Flashcards

Comprehensive vocabulary flashcards covering the key terms, organ structures, secretions, and anatomical features of the human digestive system.

Alimentary Canal

The continuous muscular tube (also known as the gastrointestinal tract or GI tract) that extends from the mouth to the anus, including the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.

Accessory Digestive Organs

Organs that assist in digestion but are not part of the alimentary canal, including the teeth, tongue, gallbladder, and digestive glands (salivary glands, liver, and pancreas).

Peristalsis

The major means of propulsion throughout the digestive tract, consisting of alternating waves of muscular contraction and relaxation.

Visceral Peritoneum

The serous membrane that directly covers the external surface of most digestive organs within the abdominal cavity.

Parietal Peritoneum

The serous membrane that lines the inner wall of the abdominopelvic cavity.

Mesentery

A double layer of fused peritoneum that extends from the body wall to hold digestive organs in place while providing pathways for blood vessels, nerves, and lymphatics.

Retroperitoneal Organs

Organs located posterior to the peritoneum, which lose their mesentery during development; includes the pancreas, duodenum, and parts of the large intestine.

Peritonitis

Inflammation of the peritoneum commonly caused by piercing abdominal wounds, perforating ulcers, or a ruptured appendix.

Parotid Gland

A major salivary gland located anterior to the ear and external to the masseter muscle.

Mumps

Inflammation of the parotid glands caused by the mumps virus (myxovirus), resulting in pain upon chewing or swallowing.

Deglutition

The complex process of swallowing that involves the coordination of 22 muscle groups across a voluntary buccal phase and an involuntary pharyngeal-esophageal phase.

Chyme

The paste-like fluid formed in the stomach through the chemical breakdown of food bolus mixed with gastric secretions.

Rugae

Large, temporary mucosal folds visible inside the stomach wall when it is empty.

Parietal Cells

Secretory cells of the gastric glands that produce hydrochloric acid (HCl, $\text{pH } 1.5 - 3.5$) and intrinsic factor.

Intrinsic Factor

A glycoprotein secreted by parietal cells in the stomach that is required for the absorption of vitamin $\text{B}_{12}$ in the small intestine.

Chief Cells

Secretory cells in the gastric glands that produce pepsinogen (the precursor to pepsin) and lipases.

Enteroendocrine Cells

Hormone-secreting cells located in the gastric glands that release regulatory chemicals such as serotonin, histamine, somatostatin, and gastrin.

Bile

A yellow-green, alkaline solution produced by the liver containing bile salts and bilirubin that serves as a fat emulsifier.

Gallstones

Crystallized deposits (biliary calculi) formed in the gallbladder due to excess cholesterol or insufficient bile salts, obstructing bile flow through the cystic duct.

Pancreatic Juice

A watery, alkaline solution ($\text{pH } 8$) secreted by the exocrine pancreas containing bicarbonate ($\text{HCO}_3^-$) and digestive enzymes for proteins, carbohydrates, lipids, and nucleic acids.

Plicae Circulares

Permanent circular folds (~1 cm deep) in the mucosa and submucosa of the small intestine that slow down chyme movement and maximize absorption.

Villi

Fingerlike projections (~1 mm high) of the small intestinal mucosa containing dense capillary networks and lacteals for nutrient absorption.

Microvilli

Tiny cytoplasmic projections on the apical surface of intestinal mucosal cells that form the brush border containing membrane-bound digestive enzymes.

Teniae Coli

Three distinct longitudinal bands of smooth muscle present in the muscularis layer of the large intestine.

Haustra

Pocketlike sacs along the length of the large intestine created by the tension of the teniae coli.

Epiploic Appendages

Small fat-filled pouches of visceral peritoneum attached to the outer surface of the large intestine.

Appendicitis

Acute inflammation of the appendix, typically presenting with initial pain near the umbilicus that shifts to the lower right quadrant of the abdomen.

Chylomicrons

Water-soluble lipoprotein vesicles assembled inside enterocytes from re-esterified triglycerides, lipids, and proteins, which exit cells via exocytosis into lacteals.