http://en.wikipedia.org/wiki/Morula

Morula

From Wikipedia, the free encyclopedia

For the South African soccer player, see Lebohang Morula.

A morula (Latin "morus", mulberry) is an embryo at an early stage of embryonic development, consisting of cells (called blastomeres) in a solid ball contained within the zona pellucida.

Production

The morula is produced by embryonic cleavage, the rapid division of the zygote. After reaching the 16-cell stage, the cells of the morula differentiate. The inner blastomeres will become the inner cell mass and the blastomeres on the surface will later flatten to form the trophoblast. As this process begins, the blastomeres change their shape and tightly align themselves against each other to form a compact ball of cells. This is called compaction and is likely mediated by cell surface adhesion glycoproteins.

Development

In mammals the morula travels to the uterus around 3-4 days after fertilization, and at about 4 days after fertilization a fluid-filled space called the blastocoelcavity appears and the morula becomes a blastocyst.