Embryonic period of development is

Development before bih is called prenatal development, and that after bih is called postnatal development. There are three stages in prenatal development. They are: 1. Preimplantation/pre-embryonic period 2. Embryonic period 3. Fetal period. Embryonic Period- It extends from 3rd week of intrauterine life to 8th week of intrauterine life. The following morphogenetic events take place during this period : 1. Trilaminar germ disc differentiation: Formation of three layered germ disc with the appearance of mesoderm in between ectoderm and endoderm. 2. Early organogenesis: Formation of primordia of various organs like lungs, hea, liver, etc. 3. Formation of extraembryonic suppoive organs and membranes: Placenta, umbilical cord, amnion, allantois. Ref:Inderbir Singh's Human Embryology, eleventh edition , pg. no.,2.