---a science which study the processes and regulations of development of human fetus.(from 1 cell(zygote) to (5-7)X1012 cells ) ---total 38 weeks: preembryonic period: before 2 weeks
1. Components: ---small gland or endocrine cell: islet of pancreas and corpus luteum ---endocrine gland: Thyroid gland Parathyroid gland Adrenal gland Pituitary gland(hypophysis) Pineal body