Physiology of Digestion and Absorption

A collection of vocabulary flashcards covering key terms and concepts related to the physiology of digestion and absorption.

Digestion

The process of breaking down complex nutrients into simple molecules.

Absorption

The process of transporting simple molecules across the intestinal epithelium into the bloodstream.

Plicae circulares

Large folds of mucosa that add to the intestinal surface area.

Villi

Fingerlike epithelial projections that increase the intestinal surface area by ten to fourteen-fold.

Brush border

A membrane composed of submicroscopic microvilli that covers the villi and further enlarges the surface area.

Enterocytes

Epithelial cells covering the villi and crypts responsible for digestive and absorptive functions.

Apical membrane

The cell membrane of enterocytes facing the lumen, containing microvilli and glycoproteins.

Basolateral membrane

The remaining portion of the enterocyte plasma membrane that plays an important function in nutrient absorption.

Tight junctions

Attachments between adjacent enterocytes that form a permeability barrier and allow selective transport of substances.

Goblet cells

Cells interspersed among enterocytes that secrete mucus to cover the mucosa.

Glycocalyx

A rich area of glycoproteins on the surface of the apical membrane involving digestive and absorptive functions.

Hydrolysis

The process of splitting a chemical bond by the insertion of a water molecule leading to simpler molecules.

Luminal phase of digestion

The digestion that occurs in the lumen of the gut, involving enzymes secreted by glands.

Membranous phase of digestion

Digestion that occurs by enzymes bound to the surface epithelium, completing the breakdown for absorption.

Colostrum

A special mammary secretion that provides antibodies to young livestock after birth.

Gut closure

The phenomenon of the disappearing specialized intestinal epithelium capable of protein absorption within 24 hours after birth.