The germinal layer of the growing human brain during early fetal life

The telencephalic vesicles of the human brain appear during the fifth week of embryonic life. These vesicles are closed containers filled with ventricular fluid until the fifteenth week when it escapes through the newly‐formed foramen of Magendie. The light and electron microscopic studies reported here support the notion that the germinal layer of the telencephalon has an absorptive role between the eighth and fifteenth weeks of fetal life. This assumption is based on the structure and the arrangement of the cells of the germinal layer, which resemble and are arranged in a manner similar to that of other absorptive units such as the renal proximal tubules, the gallbladder and the intestine. The absorbed material is presumably contained in the ventricular fluid.