absorption

…the surface area for food absorption and adding digestive secretions. The villi number about 10 to 40 per square millimetre (6,000 to 25,000 per square inch) of tissue. They are most prevalent at the beginning of the small intestine and diminish in number toward the end of the tract. They…

…size and composition, they are absorbed by the intestinal wall and transported to the bloodstream. Some food material is passed from the small intestine to the large intestine, or colon. In the colon, chyme is acted upon by bacteria that break down the proteins, starches, and some plant fibres not…

…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…

Interactions 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…

After 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…

Since 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…

, the rate of absorption increases as the molecular weight of the molecule decreases).