The Digestive System

Comprehensive vocabulary flashcards covering the anatomy, physiological processes, and enzymes of the human digestive system as presented in the lecture notes.

Alimentary canal

A one-way tube used by all animals to obtain and process food.

Digestion

The process of breaking food into smaller molecules.

Absorption

The movement of molecules into the blood stream for delivery and use by cells.

Mechanical digestion

The physical act of breaking down food by non-chemical means, such as by teeth or muscular contractions.

Chemical digestion

The chemical breakdown of food through the use of acids and enzymes, also known as enzymatic hydrolysis.

Salivary glands

Glands that secrete lubricating fluid containing enzymes, specifically salivary amylase, to break down carbohydrates.

Pharynx

An organ with muscles that propel materials into the esophagus.

Liver

An organ responsible for the secretion of bile, storage of nutrients, and many other vital functions.

Stomach

An organ that performs chemical breakdown via acid and enzymes and mechanical processing through muscular contractions.

Gallbladder

An organ used for the storage and concentration of bile.

Pancreas

A gland with exocrine cells that secrete buffers and digestive enzymes, and endocrine cells that secrete hormones like insulin and glucagon.

Small intestine

The site of enzymatic digestion and absorption of water, organic substrates, vitamins, and ions.

Large intestine

The organ responsible for dehydration and compaction of indigestible materials in preparation for elimination; also known as the colon.

Salivary amylase

An enzyme in saliva that breaks carbohydrates into monosaccharides.

Bolus

A food ball made and pushed by the tongue into the throat.

Epiglottis

A structure that protects the larynx during swallowing by closing the trachea (air tube) and opening the esophagus (food tube).

Peristalsis

The contraction of smooth muscle that pushes food down the esophagus and through the digestive tract.

Cardiac sphincter

A valve that closes the bottom of the esophagus to keep stomach contents from back-flowing.

Chyme

A mixture of fluid and food produced by the churning of the stomach.

Pepsin

An enzyme released by gastric glands in the stomach that digests proteins.

Hydrochloric acid

A chemical released in the stomach that helps activate pepsin.

Pyloric valve

A valve that releases chyme from the stomach into the small intestine.

Sodium bicarbonate

A substance produced by the pancreas that neutralizes stomach acid.

Bile

A detergent-like substance produced by the liver and stored in the gallbladder that dissolves fats so enzymes have access.

Duodenum

The upper portion of the small intestine where chemical digestion of carbohydrates, proteins, and lipids occurs via amylase, trypsin, and lipase.

Jejunum and ileum

The lower portions of the small intestine where nutrient absorption occurs across highly folded surfaces.

Villi

Large projections covering the folds of the small intestine to increase surface area for absorption; they contain blood capillaries and lacteals.

Lacteals

Lymph vessels located within the villi of the small intestine that absorb fats.

Appendix

A structure that digests cellulose using bacteria in some animals, usually herbivores.

Rectum

The final section of the large intestine where remaining material enters for elimination from the body.