MEDICAL ANIMATION TRANSCRIPT: Medication absorption is the movement of a drug from its site of administration into the blood. Oral drugs enter the stomach where they either dissolve and pass through the cell membranes of epithelial cells lining the stomach or travel undissolved through the stomach to the small intestine, which is the most common site of absorption. Here, drugs dissolve and pass through the intestinal wall. Oral drugs then travel through the portal venous system to the liver, where they undergo the first pass effect. During this process, the liver metabolizes some of the drug, either inactivating it or excreting it into bile for elimination from the body. The remaining amount of active drug leaves the liver and reaches general circulation and target organs. If a drug is administered via intravenous injection, it passes directly into the bloodstream, thus bypassing absorption in the GI tract. If administered through intramuscular or subcutaneous injection, the drug ent...