[The physiology and pathophysiology of the small intestine]

An attempt is made in this review, to highlight recent concepts in the physiology and pathophysiology of intestinal absorption, to recollect the multiplicity of functions of the small intestine in the cellular and humoral immune response and to draw attention to the numerous endocrine and paracrine cells, residing in the intestinal mucosa, which produce peptides of mostly well defined biochemistry, the physiological and especially pathophysiological role of which, however, is still uncertain.