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What is General Embryology?
Human Embryology is one of the key subjects in Anatomy and it deals with the study of the developmental events associated with human development. General embryology therefore, concentrates on those basic developmental processes occurring prior to fertilization, during fertilization and after fertilization the gestation period.
The gestation period is otherwise the period from fertilization to parturition. Clinically the period is classified into three trimesters; each spanning a period of three months i.e. First, Second and Third trimesters.
Also, the gestation period is subdivided into two developmental periods i.e. embryonic period which last for the first 8 weeks and the fetal period which spans from the 9th week to the day of birth. Each of these periods has its peculiarities.
NOTE (NB):
The embryonic period is considered as the period whereby the developing
embryo is more vulnerable to teratogens, which are toxic substances that can cause abnormal development otherwise referred to as
congenital anomalies or
abnormalities.
The vulnerability to teratogens is hinged on the fact that during the embryonic period, the basic body plan is laid down following series of cellular migration, interactions, and reorientations a characteristic feature of the embryonic embryo. In addition, this period is unique for the development of primordial structures, from which several body structures are derived (organogenesis).
On the contrary, the fetal period is less vulnerable to teratogenic insults. However, it is marked with structural differentiation and maturations.
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