(ăb-sorp'shŏn )

[L. absorptio ]

1. The taking up of liquids by solids or of gases by solids or liquids.
2. The taking up of light or its energy by black or colored rays.
3. The taking up by the body of radiant energy, causing a rise in body temperature.
4. The reduction in intensity of an x-ray photon as it passes through a substance or a beam of light as it passes through a solution (used in clinical photometry as well as nuclear methods).
5. The passage of a substance through some surface of the body into body fluids and tissues, such as the diffusion of oxygen from the alveolar air into the blood, or the active transport of amino acids from food through the epithelium of the small intestine.

carbohydrate a.The taking up of the monosaccharides by the brush border of the small intestine.

colonic a.The uptake of water, electrolytes such as sodium, amino acids, and some drugs by the mucosa of the large bowel.

cutaneous a.Absorption through the skin. SYN: percutaneous absorption .

external a.Absorption of material by the skin and mucous membrane.

fat a.The taking up of glycerols and fatty acids, suspended in bile salts, into the villi of the small intestine.

gastric a.Absorption of water, alcohol, and some salts through the gastric mucosa.

mouth a.Oral or buccal absorption of materials or medicines such as nicotine or nitroglycerin. Alkaloids are better absorbed through the oral mucosa than acidic chemicals.

parenteral a.Absorption of fluids, electrolytes, and nutrients from a site other than the gastrointestinal tract.

pathological a.Absorption of a substance normally excreted, e.g., urine, or of a product of disease processes, e.g., pus, into the blood or lymph.

percutaneous a.Cutaneous absorption.

protein a.The taking up of amino acids—singly, or linked as dipeptides or tripeptides—by the brush border of the small intestine.

small intestinal a.The uptake of water, fatty acids, monosaccharides, amino acids, vitamins, and minerals from the lumen of the gut into the capillary networks and lacteals of the villi. The small intestine is the major site of nutrient absorption in the body.