blastocyst

Blastocyst
Carnegie stage	3
Days	5
MeSH	Blastocyst
Dorlands/Elsevier	b_14/12187695

The blastocyst is an early stage of the human (or other mammal) development early in pregnancy. It is the structure formed in early human embryogenesis, after the formation of the blastocele, but before implantation. It possesses an inner cell mass, or embryoblast, and an outer cell mass, or trophoblast. The human blastocyst comprises 70-100 cells. It is preceded by a zygote, the fertilized egg cell, and succeeded by an embryo.

Recently the inner cell mass has become a source for embryonic stem cells.

External links

• Blastocyst photos at different stages of development
• Diagram at weber.edu

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

Donate to Wikimedia