The Columnar Epithelial Cell of the Small Intestine: Digestion and Transport

Abstract
DIGESTION and absorption, the specialized functions of the intestinal columnar epithelial cell, appear to be intimately dependent on processes that can be localized to the plasma membrane. They may be coupled functionally within the membrane for greater efficiency, and the many similarities between their kinetics suggest that they reflect comparable processes. For example, enzymic digestion and carrier-mediated transport may be analogous activities of protein catalysts.1 In this review we consider the digestion of carbohydrates and proteins, and the transport of the resulting monosaccharides and amino acids. Recent evidence suggests that these functions are intimately associated with the microvillus.The Columnar . . .