Development of the Human Zygote

November 16, 1995         Hundreds of thousands of times a year a single-celled zygote, little than a grain of sand, trans work outs into an amazingly complex web of cells, a newborn infant. Through cellular differentiation and growth, this bear upon is established with precision time and time again, but genuinely seldom a mistake in the blueprint of growth and exploitation does occur. following(a) is a description of how the pathways of this intricate web argon followed and the mistakes which dip out when they are not.         The impressive process of differentiation changes a single-cell into a complicated system of cells as distinct as vaporous and bone. Although fertilized eggnic development takes approximately nine months, the greatest gibe total of cellular differentiation takes place during the first ogdoad workweeks of pregnancy. This finis is called embryogenesis.         During the first week after ferti lization, which takes place in the Fallopian tube, the embryo starts to cleave once every twenty-four hours (Fig. 1). Until the eighter or sixteen cell stage, the individual cells, or blastomeres, are panorama to have the potential to form any disassociate of the foetus (Leese, Conaghan, Martin, and Hardy, April 1993). As the blastomeres continue to divide, a solid eyeball of cells develops to form the morula (Fig. 1). The accumulation of fluid inside the morula, transforms it into a hollering expanse called a blastula, which implants itself into the inner lining of the uterus, the endometrium (Fig. 1).

Th e inner pack of the blastula go forth prod! uce the embryo, while the outer(prenominal) layer of cells will form the trophoblast, which eventually will extend nourishment to the egg cell (Pritchard, MacDonald, and Gant, 1985). Figure 1: implantation process and development during embryogenesis (Pritchard, MacDonald and Gant, 1985)         During the second week of development, gastrulation, the process by which the germ layers are formed, begins to occur. The inner cell... If you call for to get a full essay, order it on our website: OrderCustomPaper.com

If you want to get a full essay, visit our page: write my paper