Structure and development of the adrenal gland of Gallus domesticus.

Abstract

The histology of the developing chick adrenal gland has been studied as a preliminary to a detailed histochemical investigation. Certain cytological observations pertaining to the Golgi apparatus and mitochondria in the cells of the gland have been made. The chromaffin component, which originates from the neural crest cells of the embryo, forms irregular islets dispersed among the cortical cords and is interconnected by strands and processes of the cells. The cortical component, which is of mesodermal origin, is organized into regular solid cylindrical cords. There appears to be a migration of cells from the periphery to the center of the cortex. The gland is richly permeated by blood sinuses and capillaries. From the last quarter of the incubation period, there is an indication of zonation in the cortex into a somewhat narrow peripheral zone and a larger central zone. The cells of the former exhibit a greater abundance of mitochondria and a smaller Golgi zone than do those of the latter. The cortex occupies a greater percent volume during embryonic life, while the medulla occupies a greater percent volume in later stages.