The structure of yellow yolk in the domestic fowl

Abstract

A microscopical study of sections of the yellow yolk in the eggs and large oocytes of the domestic fowl (Gallus domesticus) showed that the yolk mass consisted of tightly packed spheres. Each sphere was bounded by a trilaminar membrane and contained numerous subdroplets dispersed in a lighter groundwork. The subdroplets were formed, in part, of granules of mean diameter 11.4 nm; the groundwork was formed of particles of mean diameter, 26.7 nm. Lamellar bodies, 100–200 nm in diameter, were present in the groundwork of aged yolk spheres. Using intravenously injected ferritin as a tracer, it was estimated that the yolk spheres in the oocyte periphery were formed within a period of 15 min.