The anatomical relations and formation of physiological atresia in human embryogenesis.

Abstract

The process of physiological atresia is inherent in the digestive, respiratory, genitourinary and biliary systems, as well as in the natural openings of the head - the eye slit, external nasal openings, external and internal auditory canals. This phenomenon is a natural process in the development of the organism in the early stages of prenatal human ontogenesis. Tubular organs and openings temporarily lose their lumen, and then recanalization occurs that is restoration of the cavity of the organ, duct, or opening. The disappearance of epithelial occlusion has a close correlation with the formation of villi and restructuring of the epithelial layer, at this time mesenchyme tissue with vessels penetrates the epithelium from the side of the intestinal wall.