| Endometrium |
Innermost lining of the uterus; provides the surface for blastocyst implantation |
| Blastocyst |
Pre-implantation embryo; consists of three cell types: trophoblast, primitive endoderm, and inner cell mass |
| Inner cell mass |
Unpolarized pluripotent stem cells that are considered to be in the naive pluripotent state |
| Epiblast |
Pluripotent stem cells that transition from naive to primed state as cells of the ICM undergo apico-basal polarization |
| Trophectoderm/trophoblast |
Extraembryonic cells that give rise to the chorion |
| Extraembryonic primitive endoderm |
Extraembryonic cells that give rise to the yolk sac |
| Amniotic ectoderm |
Derived from epiblast cells underlying the invading trophectoderm during implantation |
| Amniotic sac |
An asymmetric cyst formed by lumenal polarization of epiblast cells, with squamous amnion cells on one side and pluripotent epiblast cells on the other side |
| Amniotic cavity |
Lumenal cavity enclosed by the amniotic sac |
| Pro-amniotic/epiblast cavity |
Lumenal cavity surrounded by recently polarized epiblast cells, before amnion fate determination |
| Gastrulation |
Developmental process by which all three embryonic germ layers are established |
| Primitive streak |
Streak-shaped domain that forms in the posterior of the embryonic disc, marking the beginning of gastrulation |
| Carnegie collection |
Collection of human embryos held at the Carnegie Institution of Washington |
| Warnock 14-d rule |
Rule that limits the research on human embryos to the first 14 d of development, based on the 1984 Report of the Committee of Inquiry into Human Fertilization and Embryology, chaired by Mary Warnock |
| Turing patterning |
Reaction-diffusion–based activator/inhibitor model of patterning, first proposed by Alan Turing in 1952 |
