morulla

blastomeres

blastocyst

embryoblast

trophoblast

embryonic stem cells
(ES cells)

cytotrophoblast

syncytiotrophoblast

hypoblast layer

epiblast

extraembryonic mesoderm

chorionic cavity

primary villi

connecting stalk

ectopic pregnancy

hydatidiform mole

gastrulation

primitive streak

primitive node

primitive pit

notochord

prechordal plate

cloacal membrane

endoderm

ectoderm

mesoderm

anterior visceral endoderm (AVE)

situs inversus

laterality sequences

primary villi

secondary villi

tertiary villi (definitive placental villus)