👉 The term "blastocoele" is used in human embryology to refer to the first developing organ of a fetus, or the beginning of an embryo. It is also known as the placental endoderm and is responsible for the formation of the innermost layer of the placenta, which helps support the developing baby's growth and development. In humans, blastocoeles are formed during the early stages of pregnancy when the mother's ovaries release eggs. The blastocyst grows
