Sandra G Smith
Ivy Tech Community College
October 7, 2011
Envision a journey of being pregnant and you are eagerly awaiting the child that you have longed for. The arrival is drawing near and you never prepared or anticipated your child being born with a defect or later displaying displaced behavioral problems. Only to find out, that the teratogens you had been exposed to or exposed your unborn child to during pregnancy, could be the cause of this abnormality. Would one remain in a constant state of fear with every food, drink, or medication they ingested? Would one remain indoors in a glass bubble? Unfortunately, one cannot hide from all of life’s environmental factors, but one can educate them self enough to know what studies have proven to be harmful teratogens to their unborn child, especially during the embryonic period.
“A teratogen is any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes. The field of study that investigates the causes of birth defects is called teratology. Some exposures to teratogens do not cause a physical defect but can alter the brain that is developing and influence cognitive and behavioral functioning, which is call behavioral teratology. The danger of structural defects caused by teratogens normally occurs earlier in the embryonic development rather than the fetal development, due to the fact it is the critical period for development of the nervous system (Santrock, Thirteenth Edition). The embryonic period is the period of prenatal development that occurs from two to eight weeks after conception. The rate of cell differentiation strengthens, support systems for cells cultivate, and organs appear. Damage during the germinal period often will prevent implantation. In the beginning of the embryonic period, blastocyst attach to the uterine wall. The mass then becomes the embryo and three layers of cells form; the embryo’s endoderm (inner layer) which will form the digestive and respiratory system, the mesoderm (middle layer) which will become the circulatory system, and the ectoderm (outermost layer) which will form the brain and the nervous system, sensory receptors, and skin parts (Santrock, Thirteenth Edition). By the time most women know they are pregnant, the major organs have began to form. While the organs are beginning to form they are most vulnerable to environmental changes. Into the third week the neural tube that eventually becomes the spinal cord has begun forming, eyes begin to form at approximately 21 days, the urogenital system becomes evident, arms and legs surface, four chambers of the heart begin to take shape, and blood vessels appear. Starting at the fifth into the eighth week; arms and legs become more distinguished, the face starts to form but is still not very recognizable, the intestinal tract develops and the facial structures fuse (Santrock, Thirteenth Edition). Birth defects are structural malformations present not only occur in the fetus but can occur after birth, having an impact on multiple organs. These defects can transpire for several reasons, including, but not limited to, exposure to teratogens, genetic factors, injury at birth, and in most cases the reasons are unknown. In the USA, one of every 33 babies will or have been born with a birth defect such as congenital heart defect, neural tube defect, cleft lip, spina bifida,
and anencephaly. All women are at risk of having a baby with a congenital defect, regardless of age, race, income or place of residence (Zhu, Kartiko, & Finell, 2009).
One of the most amazing phases of the prenatal period is the development of the brain. As the human embryo develops in the mother’s womb, the nervous system begins to form as a long hollow tube located on the embryo’s back. Approximately at the 23rd prenatal week, connections between neurons begin to occur and...
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