Electron Microscopical Studies of the Ultimobranchial Body of the Rat in Embryonic Life, with Special Emphasis on Its Fate?The Relation to the Thyroid Tissue and Parafollicular Cells

Abstract

The ultimobranchial body of mammals is usually incorporated in the thyroid gland in embryonic life. This has led some authors to call it the lateral thyroid primordium, but the problem of its further development and fate remains to be ascertained, if it produces (or is transformed into) thyroid tissue proper.