| The rudiments of the "hepatopancreas" appear early, in stage 20, as a pair of diverticula, given off from the midgut. The anterior part which lies against the yolk-sac will become the "liver". The growth of the liver exhibits a close relationship to the development of the inner yolk-sac. An electron microscopic study has been made of the hepatic epithelium at different embryonic stages. From stage 27, the cytologic aspects of the hepatic cell (presence of "balls", cytoplasm with well developed granular endoplasmic reticulum and free ribosoms...) give evidence of secretory activity. These ultrastructural features show that the liver becomes functional and allow us to think that it plays a part in the embryonic metabolism during the last stages of... |
