Structures and Functions of the Digestive System Vocabulary Flashcards

Comprehensive vocabulary flashcards covering the anatomy, enzymes, and physiological processes of the human digestive system based on lecture notes.

Alimentary canal

A long muscular open tube, also known as the digestive or Gastrointestinal tract, where organs process food for digestion, absorption, and elimination of waste.

Herbivores

Animals that have a longer digestive tract because the cellulose in their plant diet is harder to digest and requires more time.

Accessory glands

Glands that secrete digestive juices through ducts into the canal; including the salivary glands, pancreas, liver, and gallbladder.

Peristalsis

Alternating waves of contraction and relaxation in the smooth muscles lining the canal that push food along.

Sphincters

Smooth muscle ring-like valves that close off the tract to regulate the passing of materials between compartments and prevent backflow.

Salivary AMYLASE

An enzyme in saliva that helps breakdown starch (Amylose), a polysaccharide, into the disaccharide maltose.

Bolus

A softened food mass created in the mouth that is moved by the tongue to the back of the pharynx for swallowing.

Uvula

Part of the soft palate that moves up during swallowing to seal off the nasal cavity.

Epiglottis

A valve that closes the opening of the trachea (windpipe) when swallowing to prevent food from entering the lungs.

Lower esophageal sphincter

Also called the Cardiac Sphincter; a ring of muscle at the entrance of the stomach that prevents acidic contents from backing up into the esophagus.

RUGAE

Folds in the walls of the stomach that allow it to expand after a meal.

Gastric juice

A fluid secreted by gastric glands containing hydrochloric acid, salts, enzymes, water, and mucus.

CHYME

A liquid created in the stomach by the churning of food and mixing with gastric juices.

PYLORIC SPHINCTER

A valve at the end of the stomach that controls the release of chyme into the small intestine.

PEPSIN

An active protein-digesting enzyme that hydrolyzes proteins into smaller polypeptide chains.

PEPSINOGEN

The inactive form of Pepsin which requires Hydrochloric acid ($HCl$) to become activated.

PARIETAL CELLS

Cells lining the stomach that secrete Hydrochloric Acid ($HCl$).

CHIEF CELLS

Cells lining the stomach that secrete the inactive enzyme PEPSINOGEN.

DUODENUM

The first region of the small intestine after the stomach which receives secretions from the pancreas and the gall bladder.

Villi

Tiny, finger-like projections covering the folds of the small intestine to increase surface area for absorption.

JEJUNUM

The second region of the small intestine ($2.5\,m$) containing the most folds for chemical breakdown and nutrient absorption.

ILEUM

The third region of the small intestine ($3\,m$ long) that absorbs nutrients and pushes remaining undigested material into the large intestine.

Bicarbonate

A component of pancreatic fluid that changes the pH of chyme from strongly acidic ($pH\,1$) to weakly basic ($pH\,8$).

Bile

A greenish-yellow fluid mixture made of bile pigments and bile salts produced by the liver and stored in the gall bladder.

Bile salts

Essential components for fat digestion that act like detergent to physically break fat droplets into smaller droplets, increasing surface area for enzymes.