A newly developing human is typically referred to as an embryo until the ninth week after conception, when it is then referred to as a fetus. In other multicellular organisms, the word embryo can be used more broadly to any early developmental or life cycle stage prior to birth or hatching. An embryo is the early developmental stage of an animal while it is in the egg or within the uterus of the mother.
In humans the term is applied to the unborn child until the end of the seventh week following conception. An embryo is the earliest stage of a developing baby, spanning from fertilization (when sperm meets egg) through the first eight weeks of development. After those eight weeks, it’s called a fetus. : an animal in the early stages of development that are marked by cleavage, the laying down of the basic tissues, and the formation of primitive organs and organ systems compare fetus.
embryo circulation, : a tiny young plant within a seed. : a beginning or undeveloped stageused especially in the phrase in embryo. An embryo is a newly fertilized egg (zygote) up till the eighth week of development as it transforms through the morula, blastula, gastrula, and organogenesis stages. An embryo is the early stage of development and lasts from week five to week 10 of pregnancy. A fetus is the later stage of development and lasts from the end of week 10 until birth.
embryo circulation, embryo An organism in its earliest stages of development, especially before it has reached a stage at which it can be distinguished from other species. The human embryo is so called up to the eighth week after fertilization. After that it is called a fetus. Sun et al. present a stem cell-derived embryo model recapitulating certain aspects of human peri-gastrulation, including the formation of trilaminar disc-, amnion- and yolk sac-like structures.
