Embryology, Week 2-3

Excerpt

The transformation of a single cell into a complex multicellular organism is an intricate, fascinating process, entailing a series of rapid cell divisions and differentiation. The second and third weeks of embryological development are crucial, involving the implantation of the blastocyst into the uterine wall; the establishment of three distinct germ layers - the mesoderm, endoderm and ectoderm - through gastrulation; and encompass the beginnings of the neurulation process, resulting in central nervous system (CNS) development and neural tube formation. Abnormal blastocyst implantation may cause in ectopic pregnancy, hydatidiform mole or gestational trophoblastic diseases, while defects in primary neurulation are implicated in anencephaly, spina bifida, and craniorachischisis.