Embryology. Gametogenesis: spermatogenesis and oogenesis. Mitosis and meiosis. Ovulation, fertilization, segmentation and formation of the morula and blastocyst. Formation of the bilaminar and trilaminar germ disk. Origin and formation of the mesoderm and notochord. The ectoderm and its main derivatives. The endoderm and its main derivatives. The mesoderm and its main derivatives. Placenta and fetal membranes: chorion, amnion, allantois, yolk sac, umbilical cord. Structure, function and classification of placentas.