Pharmaceutics Xenobiotics Across Bio Membrane Practice Test

When you eat, splanchnic blood flow to the gut increases. Absorption across the intestinal wall depends on a concentration gradient between the lumen (where nutrients are present at high levels after a meal) and the blood. Increased blood flow helps by rapidly removing absorbed nutrients from the mucosal area, keeping the blood-side concentration low and the luminal concentration relatively high. This maintains a strong gradient, so nutrients move into the blood more readily. So absorption increases because the heightened perfusion sustains the gradient that drives net transfer.