Which route is absorbed through mucosa of the gastrointestinal tract?

• A. Intravenous
• B. Oral
• C. Inhalation
• D. Topical

Answer: (B)

Absorption through the mucosa of the gastrointestinal tract occurs when a substance is taken by mouth. The GI mucosa lining the stomach and intestines is specialized for moving small molecules into the bloodstream, so oral administration relies on this mucosal surface to enter circulation. After absorption, the substance typically goes through the liver via the hepatic portal system, which can affect its activity through first-pass metabolism.

The other routes do not use the GI mucosa: intravenous delivery puts substances directly into the bloodstream, bypassing the gut lining; inhalation uses the respiratory mucosa in the lungs; topical administration targets the skin or other non-GI mucous membranes rather than the GI tract.