Multicellular diploid eukaryote in its earliest stage of development
For other uses, see Embryo (disambiguation).
Embryo
A male human embryo seven weeks after conception (nine weeks gestational age)
Anatomical terminology
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An embryo is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals.
The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous system, and organogenesis is the development of all the various tissues and organs of the body.
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 initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of...
Embryo transfer refers to a step in the process of assisted reproduction in which embryos are placed into the uterus of a female with the intent to establish...
culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with...
Cryopreservation of embryos is the process of preserving an embryo at sub-zero temperatures, generally at an embryogenesis stage corresponding to pre-implantation...
In botany, a seed is a plant embryo and food reserve enclosed in a protective outer covering called a seed coat (testa). More generally, the term "seed"...
formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the...
Embryo loss (also known as embryo death) is the death of an embryo at any stage of its development which in humans, is between the second through eighth...
Embryo quality is the ability of an embryo to perform successfully in terms of conferring a high pregnancy rate and/or resulting in a healthy person. Embryo...
Embryo culture is a component of in vitro fertilisation where in resultant embryos are allowed to grow for some time in an artificial medium. The duration...
Embryo splitting may refer to: when spontaneous, the natural way in which identical twins are formed. when artificially induced, a method of cloning. See...
after the fertilization of an ovule to produce a fully developed plant embryo. This is a pertinent stage in the plant life cycle that is followed by dormancy...
fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own,...
the body in which it would normally be found, such as the growth of an embryo or fetus outside the mother's body, or the growth of bacteria outside the...
Embryo rescue is one of the earliest and successful forms of in-vitro culture techniques that is used to assist in the development of plant embryos that...
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm...
diagnosis (PGD or PIGD) is the genetic profiling of embryos prior to implantation (as a form of embryo profiling), and sometimes even of oocytes prior to...
will impact an embryo is dependent on several factors, such as how long the embryo has been exposed, the stage of development the embryo was in when exposed...
gametophyte — specifically termed a megagametophyte — is also called the embryo sac in angiosperms. The megagametophyte produces an egg cell for the purpose...
Embryology (from Greek ἔμβρυον, embryon, "the unborn, embryo"; and -λογία, -logia) is the branch of animal biology that studies the prenatal development...
The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called...
Embryo drawing is the illustration of embryos in their developmental sequence. In plants and animals, an embryo develops from a zygote, the single cell...
a diploid zygotic embryo. In nucellar embryony, embryos are formed asexually from the nucellus tissue. Zygotic and nucellar embryos can occur in the same...
been interpreted as embryos; embryos are also common throughout the Cambrian fossil record. Taphonomic studies indicate that embryos are preserved for longest...
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