title: [Adrenal histostructure in the postnatal ontogeny of the Greenland seal, Pagophilus groenlandica Erxleben, 1777 (Phocidae)].
abstract: Histological structure of adrenal gland is studied in four age groups of the harp seal: in adults, in two juvenile groups (6 and 1-1.5 months), and in newborns (1-1.5 days). Development of the adrenal gland in this species is analogous to that of terrestrial mammals, but also has some peculiarities of its own. Differentiation of the definitive cortex occur in the prenatal development. In the newborns it is, though weakly developed, clearly differentiated into arched, fascicle and reticular zones. The foetal cortex is discovered in newborns, which further develops in juveniles and is present (without any signs of involution and degeneration) in adults. Adrenal gland persistence was previously known in horses only, but in that case the foetal cortex was partly degenerated in adults. Chromaffin cells undergo differentiation in embryonic development, as newborns already possess two types of such cells. The final differentiation ends in juvenile of 1.5 months old.
authors.forename: F I
authors.initials: FI
authors.lastname: Mezhnin
mesh_terms: D000311:Adrenal Glands / Q000033:anatomy & histology* / Q000254:growth & development; D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D046048:Seals, Earless / Q000033:anatomy & histology* / Q000254:growth & development
vernacular_title: Gistostruktura nadpochechnika v postnatal'nom ontogeneze grenlandskogo tiulenia Pagophilus groenlandica Erxleben, 1777 (Phocidae).