Identify the mechanism of absorption of the primary metabolites. Understand how water absorption can be modified and how such alterations can lead to diarrhea and constipation. Identify why changes in motility, absorption and secretion work together to alter colonic transit. Understand how water absorption can be modified and how such alterations can lead to diarrhea and constipation. Morphology of increased surface area.
Absorption is a surface area dependent phenomenon.
The intestine is specialized structurally to maximize surface area. Therefore, in the absence of normal digestion of complex nutrients, absorption is limited. Lesser absorptive capacity exists in lower jejunum and ileum. The sugar is not metabolized, and can be used as a marker for absorption by monitoring its excretion in urine. Protein products are absorbed primarily as amino acids.