Digestive System: Vocabulary Flashcards (Digestion and Absorption)

Vocabulary flashcards covering key terms from digestion and absorption notes.

Carbohydrates

Main energy source; composed of saccharides; digested to monosaccharides for absorption.

Saccharides

Sugars; basic units of carbohydrates.

Monosaccharide

Single sugar units (e.g., glucose, fructose) absorbed by cells.

Salivary amylase

Enzyme in saliva that begins carbohydrate digestion by breaking down starch.

Pancreatic amylase

Pancreatic enzyme that continues starch digestion in the small intestine.

Maltase

Brush border enzyme that splits maltose into two glucose molecules.

Sucrase

Brush border enzyme that splits sucrose into glucose and fructose.

Lactase

Brush border enzyme that splits lactose into glucose and galactose.

Lingual lipase

Lipase secreted on the tongue; inactive until stomach acidity activates it; begins lipid digestion.

HCl

Hydrochloric acid secreted by stomach parietal cells; activates pepsinogen, aids digestion and sterilizes.

Pepsinogen

Inactivated enzyme secreted by chief cells; activated to pepsin by acid.

Pepsin

Protease that digests proteins in the stomach.

Intrinsic factor

Glycoprotein secreted by parietal cells; essential for vitamin B12 absorption.

Chyme

Partially digested food that leaves the stomach.

Pyloric sphincter

Valve that controls emptying of the stomach into the duodenum.

Stomach

Sac that stores and mechanically/chemically digests food; forms chyme.

Mucous cells

Mucus-secreting cells protecting stomach lining.

Chief cells

Secrete pepsinogen, the inactive form of pepsin.

Parietal cells

Secrete HCl and intrinsic factor.

Enteroendocrine cells

Hormone-secreting cells regulating digestion (e.g., G cells).

G cells

Enteroendocrine cells that secrete gastrin.

Gastric glands

Glandular region in stomach containing mucous, chief, parietal, and enteroendocrine cells.

Brunner’s glands

Duodenal glands that secrete alkaline mucus to neutralize stomach acid.

Small intestine

Primary site of digestion and absorption; includes duodenum, jejunum, ileum.

Duodenum

First section of small intestine; receives chyme, pancreatic juices, bile.

Jejunum

Main site of nutrient absorption.

Ileum

Absorbs bile acids and vitamin B12; last portion of small intestine.

Enterocytes

Absorptive cells lining the small intestine.

Goblet cells

Mucus-secreting cells in the intestinal lining.

Brush border

Surface of enterocytes lined with microvilli containing digestive enzymes.

Microvilli

Small projections on enterocytes increasing surface area.

Villi

Finger-like folds increasing surface area for absorption.

Lacteal

Lymphatic vessel inside a villus, transporting fats.

Capillaries

Blood vessels in a villus absorbing sugars and amino acids.

Iron absorption

Process by which iron is absorbed in the small intestine; involves reduction/oxidation states.

Heme iron

Iron from heme; more easily absorbed.

Non-heme iron

Iron not from heme; absorption influenced by oxidation state.

Feces

Solid waste excreted; composed of water, bacteria, undigested material.