The trophoblast (from Greek trephein: to feed; and blastos: germinator) is the outer layer of cells of the blastocyst. Trophoblasts are present four days after fertilization in humans. [1]

The trophoblast originates from the trophectoderm (see below) and differentiates into multiple specialized trophoblast subpopulations and phenotypes. They either differentiate into polar cells …

The intermediate trophoblast on the villous surface forms trophoblastic columns that anchor the fetal part of placenta to the implantation site. In all other locations, the trophoblast is referred to as extravillous …

trophoblast: The membrane of cells that forms the wall of a blastocyst during early pregnancy, and also provides nutrients to the embryo and later develops into part of the placenta.

During this period the trophoblast layer proliferates and differentiates into two distinct layers (syncitiotrophoblast and cytotrophoblast). Following implantation, trophoblast cells continue to …

The initial layer of trophoblast cells, known as the trophectoderm, is contiguous with the embryonic ectoderm. As pregnancy progresses, trophoblasts undergo rapid proliferation and differentiation, …

Mar 24, 2026 · A trophoblast is the outer layer of cells that forms on an embryo roughly four to five days after fertilization. These cells never become part of the baby. Instead, they build the placenta and …

The trophoblast plays an important role later in the development of the placenta or afterbirth. The conceptus makes contact with the uterine lining about the fifth or sixth day after conception.…

The trophoblast During implantation the trophoblast differentiates itself into two layers: the syncytiotrophoblast (ST) the cytotrophoblast (CT) The syncytiotrophoblast forms an external layer …

Here, the protein-coding genes expressed in trophoblast cells are described and characterized, together with examples of immunohistochemically stained tissue sections that visualize corresponding protein …