COMPLEX HISTOLOGICAL, HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL STUDY OF THE HUMAN APPENDIX IN THE LATE PRENATAL ONTOGENESIS WAS PERFORMED

It has been established that epithelial lining, loose fibrous connective tissue and smooth muscle cells develop from the midgut endoderm and autochthonous mesenchyme. Since the appearance up to 12-16 weeks of human fetal development the appendix epithelium is pseudostratified columnar. In this period the epithelium forms villi-like projections. After 16-18 weeks these projections disappear. Pseudostratified columnar epithelium of the appendix synthesizes glycogen. During the differentiation the cuboidal cell are converted to the prismatic. On its surface microvilli and glycocalyx consisting of proteoglycans are defined. At 19-21 week of intrauterine life goblet cells are differentiated among high prismatic epithelial cells. Signs of goblet cell secretion are observed in 21-22 weeks of human fetal development. Histochemically PAS-positive substance is revealed in the cytoplasm of secreting goblet cells and in secret on the surface epithelium of the appendix mucosa. In the composition of this substance sialic acid and neutral polysaccharides are dominated.