Stages of Development Essay Example | Topics and Well Written Essays - 500 words

Stages of Development - Essay ExampleProgesterone levels also shoot up during pregnancy and dish to cause loosening of ligaments and joints throughout the body, cause internal organs such as ureters to enlarge and importantly transform the uterus to a size that can accommodate a full pregnancy. The hormones make engagement difficult because of the loosened ligaments. The womans posture changes, breast enlarge, abdomen transform into a convexo-concave shape increasing the curvature of her back (which may often result in changes in aesthesis of balance). Weight gain during pregnancy slows down blood and fluid circulation. As a result, pregnant women protect fluids and experience swelling of legs, feet, hands and even face. Some women experience vision changes during pregnancy characterized by increase myopia and abnormal hair and nail growth rates. Apart from increased metabolic rates collectible to high demands for nutrients, women also experience taste and smell changes a fore sighted with skin changes such as teaching of stretch marks (Fuchs, 1983).In the third week of pregnancy, gastrulation begins with the appearance of a primitive streak which establishes the long axis of the embryo. Gastrulation involves the transformation of the two-layered embryonic disc into a three layered embryo with three elemental germ layers the ectoderm (develops into the epithelial lining of the gut, respiratory and urogenital organisations and associated glands), the mesoderm (develops into all tissues not make by ectoderm or endoderm such as the muscle tissue) the endoderm (develops into structures of the nervous system and the epidermis) (Goodwin, 1994).Fertilization of the egg by the sperm results in the formation of a zygote which travels down the fallopian tube-shaped structure and divides into a ball of cells. The zygote continues to divide into an inner group of cells with an outer shell collectively called the blastocyst. blastodermic vessicle moves to the ut erus around day 5 and implants onto the uterine wall around day 6 for nourishment.