absorption
Quick Summary
Absorption in physiology refers to the process by which digested nutrients move from the digestive tract into the bloodstream or lymphatic system. This primarily occurs in the small intestine, which has a massive surface area due to folds, villi, and microvilli.1
There are four main mechanisms of absorption:
* Active transport: Requires energy to move substances against a concentration gradient.2
* Passive diffusion: Substances move from high to low concentration without energy or a carrier.2
* Facilitated diffusion: Uses a carrier molecule but no energy.2
* Endocytosis: The cell membrane engulfs the material to be absorbed.2
The duodenum and jejunum are key sites for absorption, where digestive enzymes and secretions neutralize acids and prepare nutrients. Water and electrolytes like sodium and potassium are also absorbed throughout the small intestine. For drugs, absorption into the bloodstream can occur in the stomach and intestine, with the rate influenced by factors like food presence and drug preparation.23
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therapeuticsPrinciples of drug uptake and distribution…be effective, it must be absorbed and distributed throughout the body. Drugs taken orally may be absorbed by the intestines at different rates, some being absorbed rapidly, some more slowly. Even rapidly absorbed drugs can be prepared in ways that slow the degree of absorption and permit them to remain…
Read More…be effective, it must be absorbed and distributed throughout the body. Drugs taken orally may be absorbed by the intestines at different rates, some being absorbed rapidly, some more slowly. Even rapidly absorbed drugs can be prepared in ways that slow the degree of absorption and permit them to remain…
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pharmaceutical industryDrug interactionsInteractions during drug absorption may lower the amount of drug absorbed and decrease therapeutic effectiveness. One such interaction occurs when the antibiotic tetracycline is taken along with substances such as milk or antacids, which contain calcium, magnesium, or aluminum ions. These metal ions bind with tetracycline and produce…
Read MoreInteractions during drug absorption may lower the amount of drug absorbed and decrease therapeutic effectiveness. One such interaction occurs when the antibiotic tetracycline is taken along with substances such as milk or antacids, which contain calcium, magnesium, or aluminum ions. These metal ions bind with tetracycline and produce…
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drugAbsorptionAfter oral administration of a drug, absorption into the bloodstream occurs in the stomach and intestine, which usually takes about one to six hours. The rate of absorption depends on factors such as the presence of food in the intestine, the particle size of…
Read MoreAfter oral administration of a drug, absorption into the bloodstream occurs in the stomach and intestine, which usually takes about one to six hours. The rate of absorption depends on factors such as the presence of food in the intestine, the particle size of…
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nutritionCompetition for sites of absorption by the cellSince absorption of nutrients frequently occurs by way of active transport within cell membranes, an excess of one nutrient (A) may inhibit absorption of a second nutrient (B), if they share the same absorption pathway. In such cases, the apparent requirement…
Read MoreSince absorption of nutrients frequently occurs by way of active transport within cell membranes, an excess of one nutrient (A) may inhibit absorption of a second nutrient (B), if they share the same absorption pathway. In such cases, the apparent requirement…
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, the rate of absorption increases as the molecular weight of the molecule decreases).
Read More, the rate of absorption increases as the molecular weight of the molecule decreases).
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