A documented scheme of the early development of the human endocrine system is presented. It is based on (1) reports of workers who personally studied staged embryos, and (2) personal observations and confirmations. The necessity of using staged embryos in order to determine the precise sequence of developmental events is stressed.
Key words Human embryo - Endocrine system - Hypophysis cerebri - Thyroid gland - Developmental stages
Supported by research grant No. HD-16702, Institute of Child Health and Human Development, National Institutes of Health (U.S.A.)