Examination of the Microflora of the Colon

Abstract

Relevance of the study. The human thymus is laid at the beginning of the second month of development in embryos from two sources: ecto- and endoderm of the ventral walls of the third pharyngeal pockets and slits in the form of two separate rudiments (future right and left lobes of the organ), which approach as closely as possible by the middle of the second month of prenatal ontogenesis. By the middle of the 3rd month of human intrauterine development, the thymus acquires a definitive structure: lobules, cortical and cerebral matter are formed in its lobes and thymus corpuscles are found. The growth of the thymus in prenatal human ontogenesis is characterized by a wave–like course, there are three periods of accelerated growth: the first – in the middle of the second month (associated with the ingrowth of vessels into the thymus and the colonization of the epithelial lining of the organ by lymphoid cells), the second - at the end of the 3rd month (associated with the completion of organogenesis), the third – 6-8 months development (corresponds to the active growth of the fetus [1.3.5.7].