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 profit of cells, a newborn infant. Through cellular differentiation and growth, this bring is established with precision time and time again, but real seldom a mistake in the blueprint of growth and emergence does occur. following(a) is a description of how the pathways of this intricate web argon followed and the mistakes which surpass 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 state total of cellular differentiation takes place during the first ogdoad workweeks of pregnancy. This finis is called embryogenesis.         During the first week after fertiliza tion, which takes place in the Fallopian tube, the embryo starts to cleave once every twenty-four hours (Fig. 1). Until the viii or sixteen cell stage, the individual cells, or blastomeres, are panorama to have the potential to form any furcate of the foetus (Leese, Conaghan, Martin, and Hardy, April 1993). As the blastomeres continue to divide, a solid junkie of cells develops to form the morula (Fig. 1). The accumulation of fluid inside the morula, transforms it into a hollo expanse called a blastula, which implants itself into the inner lining of the uterus, the endometrium (Fig. 1).

The inner plentifu lness of the blastula go forth produce the ! embryo, while the out layer of cells will form the trophoblast, which eventually will admit nourishment to the egg cell (Pritchard, MacDonald, and Gant, 1985). Figure 1:nidation 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

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