Development of the Human Zygote

November 16, 1995         Hundreds of thousands of times a year a single-celled zygote, smaller than a grain of sand, trans work outs into an amazingly complex mesh of cells, a newborn infant. Through cellular differentiation and growth, this passage is established with precision time and time again, but very seldom a mistake in the blueprint of growth and teaching does occur. following(a) is a description of how the pathways of this intricate web atomic number 18 followed and the mistakes which attend 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 warmness total of cellular differentiation takes place during the first 8 workweeks of pregnancy. This finis is called embryogenesis.         During the first week after fertilization, which takes place in the Fallopian tube, the embryo starts to cleave once every twenty-four hours (Fig. 1). Until the octette or sixteen cell stage, the individual cells, or blastomeres, are panorama to have the potential to form any originate of the foetus (Leese, Conaghan, Martin, and Hardy, April 1993). As the blastomeres continue to divide, a solid lout of cells develops to form the morula (Fig. 1). The accumulation of fluid inside the morula, transforms it into a labor expanse called a blastula, which implants itself into the inner lining of the uterus, the endometrium (Fig. 1).

The inner muckle of the blastula go forth produce the embryo, while the outer(p renominal) layer of cells will form the trop! hoblast, which eventually will appropriate 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: OrderEssay.net

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