Consisting of four main specialized cell lineages: absorptive enterocytes and three secretory cell types known as enteroendocrine, Paneth, and goblet cells; plus, a rare, fifth type of intestinal cell called tuft cells that also exist.

Defined by the thick brush of long microvilli that project from their apical surface, tuft cells are seen in several epithelial tissues, yet little is known about their functions because there is a lack of tuft cell–specific markers.