The Mircle of Life- Prenatal Development

2119 words 9 pages
Prenatal Development-The Miracle of Life
Have you ever thought about what an absolute miracle your life is? Imagine how you came to be. Out of thousands of eggs and millions of sperm, one egg and one sperm united to produce you. Had the union of sperm and egg come a day or even a month earlier or later, you might have been every different, maybe the opposite sex or with blonde hair of longer legs. Conception occurs when a single sperm cell from the male unites with an ovum (egg) in the females’ fallopian tube in process call fertilization. The fertilized egg is called a zygote. By the time the zygote ends its three to four day journey through the fallopian tube and reaches that uterus, it has divided into approximately 64 to 128 cells
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Before most women know they are pregnant some important embryonic developments, such as organogenesis, take place. Organogenesis is the process of organ formation that takes place during the first two months of prenatal development. In the third week, the neural tube forms, this structure eventually will become the brain and spinal cord. At about 21 days, eyes begin to appear, and at 24 days the cells for the heart begin to differentiate. During the fourth week, the first appearance of the urogenital system is apparent, and arm and leg buds emerge. Four chambers of the heart take shape, and blood vessels surface. From the fifth to the eighth week, arms and legs differentiate further; at this time the face starts to form but still is not very recognizable. While organs are being formed, they are especially vulnerable to environmental changes (Wehrens & others, 2004).
The fetal period is the prenatal period of development that begins two months after conception and lasts for about seven months, on the average. Growth and development continue their dramatic course during this time. Three months after conception, the fetus is about three inches long and weighs about one ounce. It has become active, moving its arms and legs, opening and closing its mouth, and moving its head. The face, forehead, eyelids, nose, and chin are distinguishable, as are the upper