General outline small digestive glands distributed in the wall of digestive tract esophageal glands, gastric glands and intestine glands large digestive glands outside the wall of digestive tract salivary glands, liver and pancreas
---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