The fine structure of the esophagus of some trichuroid nematodes. I. The stichosome of Capillaria hepatica, Trichuris myocastoris, and Trichuris vulpis

Abstract

The posterior glandular esophagus (stichosome) of the trichuroids Capillaria hepatica, Trichuris myocastoris, and T. vulpis has been found to include three components: the large gland cells or stichocytes, the lumenal epithelium with its cuticular lining, and an external muscle reticulum surrounding the entire stichosome. A pore, composed in C. hepatica of a local thickening of the lumenal cuticle, connects the lumen to a branching system of intracellular collecting ducts in the stichocytes that receive the secretory products (granules and vesicles) formed in the cell. A system of filament bundles within the stichocyte cytoplasm probably suspends the collecting duct system within the cell. Opening and closing of the esophageal lumen appears to occur through contraction of the external muscle reticulum, as the lumenal epithelium either lacks myofilaments entirely (C. hepatica), or retains only vestigial clumps of them (T. vulpis).