ABSTRACT
This chapter summarizes evidence for various physiological factors governing the digestion and absorption of food. The rate of digestion and absorption of fats in the small intestine depends on numerous factors. These include the growth and differentiation of the mucosa, the supply of energy, composition of the chyme, rate of gastric emptying, peristaltic activity in the small intestine, enzymatic degradation into absorbable products, and membrane transport. In order to permit both the replicative differentiation and absorptive functions of the enterocytes, the intestinal mucosa is efficiently supplied with metabolic fuels. The effect of general hormones on the metabolism of the gut wall has been extensively investigated as has been that of the specific gut hormones. Pancreatic growth and maturation is essential for fat absorption because of the lipases and other enzymes that this organ releases into the intestine. Biliary secretion makes available bile salts for the emulsification of lipids during digestion and for the formation of lipid micelles during fat absorption.
