part_of part of organ digestive tract alimentary system intestine WBPaper:00038216 WBbt:0005772 mesenteron gut worm_anatomy LINKOUT::WORMATLAS::<http://wormatlas.org/ver1/handbook/alimentary/alimentary2.htm> A chain of very large cuboidal cells forming a wide central lumen in which food arrives from the posterior pharynx, is digested, and from which waste products proceed to the rectum. Intestinal rings form in groups of two and four cells surrounding the common lumen; thus the epithelium is only one cell deep at any point, with neighboring cells firmly secured to their neighbors by apical adherens junctions. These cells have very large nuclei and many large vacuoles, yolk granules, and other inclusions; the latter increase in number and electron density as the animal ages.