Prenatal Development and Birth Essay

530 WordsAug 9, 20123 Pages
6/19/2012 Prenatal Development and Birth One of the greatest events in human life is that, that occurs in the very beginning of life. Prenatal development is the process in which a baby is formed inside the uterus of a woman. The process is intense and includes the time of conception until birth. The process is divided into three stages: the germinal stage, the embryonic stage, and the fetal stage. The three stages of prenatal development is always followed by birth, a process all of its own. The germinal stage starts with fertilization, when the sperm unites with an egg in a fallopian tube. When the egg is fertilized it is called a zygote, its first journey is down the fallopian tube towards the uterus. It is a long trip that can take up to a week, all the while on this journey the zygote is dividing and growing. Once the zygote has divided multiple times the zygote changes into a blastocyst. The blastocyst is made up of 3 layers. The ectoderm, the endoderm and the mesoderm. When the blastocyst reaches the uterus it attaches itself to the uterine wall, this is called implantation. After about three weeks from conception we reach the embryonic stage, and the blastocyst is now known as the embryo. This is when the cells have become a distinct human being. The embryo begins to divide into 3 layers each will become an important body system. Around the fourth week the head is forming, followed by the eyes, nose, ears and mouth. The cardiovascular system starts to pulse making it the earliest organ system to function. During the 5th week, the arms and legs are beginning to form. The embryo will have all basic organs and parts except sex organs, by the 8th week. At this point the fetal stage begins. The cell differentiation is all most complete by this stage and the embryo is now a fetus. This is the longest stage of prenatal development; it starts at 9

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