Morula

For the South African soccer player, see Lebohang Morula.

Morula
Blastulation. 1 - morula, 2 - blastula.
First stages of segmentation of a fertilized mammalian ovum. Semidiagrammatic. z.p. Zona pellucida. p.gl. Polar bodies. a. Two-cell stage. b. Four-cell stage. c. Eight-cell stage. d, e. Morula stage.
Gray's	subject #6 46
Days	3
Precursor	Zygote
Gives rise to	Blastula, Blastocyst
Code	TE E2.0.1.2.0.0.11

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.^[1]

The morula is produced by embryonic cleavage, the rapid division of the zygote. Once the zygote has divided into 32 cells, it begins to resemble a mulberry, hence the name morula (Latin, morus: mulberry).^[2] Within a few days after fertilization, cells on the outer part of the morula become bound tightly together with the formation of desmosomes and gap junctions, becoming nearly indistinguishable. This process is known as compaction.^[3][4] The cells of the morula then secrete a viscous liquid^[specify], causing a central cavity to be formed, forming a hollow ball of cells known as the blastocyst.^[5][6] The blastocyst's outer cells will become the first embryonic epithelium (the trophectoderm). Some cells, however, will remain trapped in the interior and will become the inner cell mass(ICM), and are pluripotent. In mammals (except monotremes), the ICM will ultimately form the "embryo proper", while the trophectoderm will form the placenta and other extra-embryonic tissues.^{[7][8][9][10]}

See also

• Cleavage (embryo)
• Blastula

References

1. ^ Boklage, Charles E. (2009). How New Humans Are Made: Cells and Embryos, Twins and Chimeras, Left and Right, Mind/Self/Soul, Sex, and Schizophrenia. World Scientific. p. 217. ISBN 9789812835130. http://books.google.com/books?id=j7GfgRIgP9YC&pg=PT233. 
2. ^ Sherman, Lawrence S. et al., ed (2001). Human embryology (3rd ed.). Elsevier Health Sciences. p. 20. ISBN 9780443065835. http://books.google.com/books?id=H5qw-jiMc44C&pg=PA20. 
3. ^ Chard, Tim & Lilford, Richard (1995). Basic sciences for obstetrics and gynaecology. Springer. p. 18. ISBN 9783540199038. http://books.google.com/books?id=MsPsw4ejMxwC&pg=PA18. 
4. ^ Mercader, Amparo et al. (2008). "Human embryo culture". In Lanza, Robert & Klimanskaya, Irina. Essential stem cell methods. Academic Press. p. 343. ISBN 9780123747419. http://books.google.com/books?id=aPcvphPV6AgC&pg=PA343. 
5. ^ Patestas, Maria Antoniou & Gartner, Leslie P. (2006). A textbook of neuroanatomy. Wiley-Blackwell. p. 11. ISBN 9781405103404. http://books.google.com/books?id=JEEnkNuuYkoC&pg=PA11. 
6. ^ Geisert, R.D. & Malayer, J.R. (2000). "Implantation: Blastocyst formation". In Hafez, B. &. Reproduction in farm animals. Wiley-Blackwell. p. 118. ISBN 9780683305777. http://books.google.com/books?id=baz2TC1y2esC&pg=PA118. 
7. ^ Morali, Olivier G. et al. (2005). "Epithelium-Mesenchyme Transitions are Crucial Morphogenetic Events Occurring During Early Development". In Savagner, Pierre. Rise and fall of epithelial phenotype: concepts of epithelial-mesenchymal transition. Springer. p. 16. ISBN 9780306482397. http://books.google.com/books?id=3a54uGVK03cC&pg=PA16. 
8. ^ Birchmeier, Carmen et al. (1997). "Morphogenesis of epithelial cells". In Paul, Leendert C. & Issekutz, Thomas B.. Adhesion molecules in health and disease. CRC Press. p. 208. ISBN 9780824798246. http://books.google.com/books?id=vLqxqS0iZkYC&pg=PA208. 
9. ^ Nagy, András (2003). Manipulating the mouse embryo: a laboratory manual. CSHL Press. pp. 60–61. ISBN 9780879695910. http://books.google.com/books?id=4juoa5xMs8oC&pg=PA60. 
10. ^ Connell, R.J. & Cutner, A. (2001). "Basic Embryology". In Cardozo, Linda & Staskin, David. Textbook of female urology and urogynaecology. Taylor & Francis. p. 92. ISBN 9781901865059. http://books.google.com/books?id=EMMUyiKOOiEC&pg=PA92. 

Further reading

• "Regulative development in mammals"