Trophoblast

Introduction

(Greek, trophe = "nutrition" and -blast, a primordial cell) the trophoblast cells have an important contribution to extraembryonic tissues (fetal placenta and membranes) and processes of early development (adplantation, implantation and endocrine support of pregnancy). Week 1 blastocyst formation the outer layer of cells (adjacent to the zona pellucida) form a flat squamous epithelial layer of cells, the trophoblast layer. Week 2 following blastocyst hatching the trophoblast layer is involved with initial adhesion to the uterine wall and subsequent implantation within the wall. During this period the trophoblast layer differentiates into two distinct layers (syncitiotrophoblast, cytotrophoblast).

(More? Week 2 Notes | Week 3 Notes | Placenta Notes)