The Digestive System – Vocabulary Review

A comprehensive set of 99 vocabulary flashcards covering structures, enzymes, and functions of the human digestive (gastrointestinal) system.

Digestive System

Collection of organs that ingest food, break it down, absorb nutrients, and eliminate wastes.

Gastrointestinal (GI) System

Portion of the digestive system made up of the GI tract plus accessory organs.

Gastrointestinal Tract

Long, twisting tube from mouth to anus through which food travels.

Mouth (Oral Cavity)

Entrance of the GI tract where food is bitten, chewed, mixed with saliva, and swallowed.

Salivary Glands

Exocrine glands that secrete saliva into the oral cavity.

Lips

Fleshy structures forming the mouth opening, aiding in food intake and speech.

Cheeks

Lateral walls of the oral cavity that keep food between upper and lower teeth.

Buccinator Muscle

Cheek muscle preventing food from slipping between teeth and gums during chewing.

Palatoglossal Muscle

Tongue muscle extending from soft palate; helps move tongue during swallowing.

Palatopharyngeal Muscle

Muscle in soft palate forming roof of mouth and assisting the swallowing reflex.

Saliva

Watery secretion that moistens food, contains enzymes, buffers, and antimicrobial agents.

Parotid Gland

Largest salivary gland located below the ear and over the masseter muscle.

Submandibular Gland

Salivary gland found beneath the lower edge of the mandible.

Sublingual Gland

Small salivary gland deep to the tongue in the floor of the mouth.

Bicarbonate Ions

Components of saliva that neutralize acidic foods.

Salivary Amylase

Enzyme in saliva that starts starch digestion at pH 6.5–7.0.

Lysozyme

Antibacterial enzyme in saliva that helps destroy oral microbes.

Mechanical Digestion

Physical breakdown of food by chewing, churning, or segmentation.

Mastication

Chewing process that breaks food into smaller pieces and mixes it with saliva.

Bolus

Soft, flexible mass of food formed in the mouth ready for swallowing.

Chemical Digestion

Enzymatic conversion of macromolecules into absorbable units.

Lingual Lipase

Enzyme secreted by tongue glands that begins triglyceride breakdown.

Pharynx

Funnel-shaped muscular tube connecting nasal cavity to esophagus and larynx.

Oropharynx

Middle region of pharynx behind the oral cavity where swallowing begins.

Esophagus

25-cm muscular tube that transports food from pharynx to stomach.

Deglutition

The act of swallowing food or liquid.

Deglutition Center

Brainstem nuclei that coordinate the swallowing reflex.

Cricoid Cartilage

Ring-shaped cartilage at C6 marking the upper start of the esophagus.

Cardiac Orifice

Opening where the esophagus enters the stomach.

Adventitia

Outer connective tissue layer of the esophagus and other retroperitoneal GI organs.

Longitudinal Muscle Layer

External smooth muscle fibers running lengthwise along the GI tract.

Circular Muscle Layer

Inner smooth muscle fibers encircling the GI tract that constrict the lumen.

Submucosa

Layer of loose connective tissue containing vessels, nerves, and glands beneath mucosa.

Mucosa

Innermost lining of the GI tract involved in secretion and absorption.

Stratified Squamous Epithelium

Protective multilayered lining of the esophagus and oral cavity.

Columnar Epithelium

Single-layered mucosa of stomach and intestines specialized for secretion and absorption.

Upper Esophageal Sphincter

Muscular ring at the pharyngo-esophageal junction controlling entry into the esophagus.

Air Entry Prevention

UES function that stops excess air from entering the digestive tract while breathing.

Reflux Prevention

UES action that keeps esophageal contents from re-entering the pharynx and airway.

Lower Esophageal Sphincter

Muscle ring at the gastro-esophageal junction preventing gastric reflux.

Gastro-esophageal Junction

Transition point between esophageal squamous and gastric columnar mucosa at T11.

Stomach

J-shaped sac in the upper left abdomen that stores, mixes, and digests food.

Cardia

Upper region of the stomach surrounding the esophageal entry.

Fundus

Dome-shaped region of the stomach located under the diaphragm beside the cardia.

Body (Corpus)

Largest central section of the stomach where most mixing occurs.

Antrum

Lower stomach chamber that holds food before emptying into the duodenum.

Pylorus

Distal region of the stomach leading to the small intestine.

Pyloric Sphincter

Muscular valve controlling the release of chyme into the duodenum.

Chyme

Semi-liquid mixture of partially digested food and gastric secretions.

Food Storage (Stomach)

Temporary holding of ingested material until it can be processed further.

Gastric Mixing

Rhythmic stomach contractions that blend food with gastric juice.

Hydrochloric Acid

Strong acid secreted by the stomach that lowers pH and activates enzymes.

Pepsin

Active protease in the stomach that digests proteins in acidic conditions.

Protease

General term for enzymes that break down proteins.

Acidic Environment

Low gastric pH that denatures proteins and activates digestive enzymes.

Microorganism Destruction

Protective role of gastric acid against ingested pathogens.

Small Intestine

Approximately 6-meter tube where most chemical digestion and nutrient absorption occur.

Chemical Absorption

Uptake of digested nutrients through the intestinal mucosa.

Mechanical Action (Small Intestine)

Segmentation and peristalsis that mix chyme and move it forward.

Large Intestine

Wider tube that absorbs water, electrolytes, vitamins, and forms feces.

Electrolyte Absorption

Uptake of ions like sodium and chloride in the large intestine.

Water Absorption

Removal of water from chyme in the colon to form solid stool.

Vitamin B Absorption

Uptake of B-complex vitamins produced by colonic bacteria.

Vitamin K Absorption

Absorption of bacteria-synthesized vitamin K in the colon.

Rectum

Terminal portion of the large intestine that stores feces before elimination.

Anus

External opening of the GI tract through which defecation occurs.

Defecation

Elimination of feces via the rectum and anus.

Pancreas

Retroperitoneal gland with both exocrine digestive and endocrine hormonal roles.

Exocrine Function

Secretion of pancreatic juice containing enzymes into the duodenum.

Endocrine Function

Release of hormones from pancreatic islets into the bloodstream.

Pancreatic Enzymes

Digestive proteins such as lipase, protease, and amylase secreted by the pancreas.

Pancreatic Lipase

Pancreatic enzyme that hydrolyzes dietary fats.

Pancreatic Protease

Enzyme group (e.g., trypsin) that digests proteins in the small intestine.

Pancreatic Amylase

Enzyme that continues starch breakdown in the small intestine.

Insulin

Beta-cell hormone that lowers blood glucose by promoting cellular uptake.

Glucagon

Alpha-cell hormone that raises blood glucose by stimulating glycogen breakdown.

Blood Glucose Regulation

Balance between insulin and glucagon maintaining normal serum sugar levels.

Liver

Large metabolic organ in the right upper abdomen performing detoxification and synthesis.

Right Upper Quadrant

Abdominal region where most of the liver is situated.

Detoxification

Hepatic conversion of drugs and toxins into less harmful compounds.

Protein Synthesis (Liver)

Production of plasma proteins such as albumin and clotting factors.

Bile Production

Secretion of fluid by the liver that emulsifies fats in the small intestine.

Cholesterol Production

Hepatic manufacture of cholesterol and lipid transport proteins.

Glycogen Conversion

Storage of excess glucose as glycogen (glycogenesis) in the liver.

Drug Clearance

Removal of medications from the blood by hepatic metabolism.

Bilirubin Clearance

Excretion of heme-breakdown pigment via bile.

Jaundice

Yellowing of skin and eyes caused by excess bilirubin.

Bile Function

Emulsifies dietary fats to increase surface area for lipase action.

Gallbladder

Small sac beneath the liver that stores and concentrates bile.

Appendix

Narrow tube attached to the cecum; considered part of the large intestine.

Skeletal Muscle of Pharynx

Voluntary muscle forming pharyngeal walls to propel food during swallowing.

Mucous Membrane

Protective lining that secretes mucus in the pharynx and GI tract.

Swallowing Lubrication

Role of saliva and mucus in easing bolus passage through the pharynx.

Airway Aspiration Prevention

Function of sphincters to stop stomach contents entering the respiratory tract.

Gastric Sphincters

Collective term for the inferior esophageal and pyloric sphincters controlling entry and exit.

Digestive Enzymes

Biological catalysts like amylase, lipase, and protease that facilitate food breakdown.

Carbohydrate Digestion

Conversion of starches to sugars beginning with salivary and pancreatic amylase.

Protein Digestion

Breakdown of proteins by pepsin in the stomach and pancreatic proteases.

Fat Digestion

Hydrolysis of triglycerides by lingual and pancreatic lipases.