Final answer:
The term 'blastocyst' in medical parlance describes an early stage in mammalian embryonic development, which is marked by a fluid-filled cavity called the blastocoel and differentiation into the inner cell mass and the trophoblast.
Step-by-step explanation:
The medical term blastocyst refers to a particular stage in embryonic development following fertilization. A blastocyst is a structure formed in the early development of mammals, such as humans, and consists of approximately 100 cells. It has two main parts: the embryoblast (or inner cell mass) which will develop into the embryo, and the trophoblast, an outer layer that will become the associated fetal membranes and the placenta. Another feature of a blastocyst is the blastocoel, a fluid-filled cavity within the blastocyst. The term 'blastocyst' illustrates the stage where the conceptus (early embryo) has formed this fluid-filled cavity and differentiated into these distinct cellular components, laying the groundwork for further development and implantation in the uterus.