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Human Development from Conception to Birth

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There are many reasons that certain drugs damage to an embryo very early in pregnancy even before the mother realizes she is pregnant. Firstly, some of the mother already exposed to certain drugs before she get pregnant such as tobacco and alcohol. For example, the women who take cigarettes everyday in their daily life will continue to smoke before they realize it. Due to this, the babies of mother who smoke tend to grow more slowly in the womb and are likely to be born prematurely and small (Habek et al., 2002). Apart from that, some of the women did not go to consult doctor when they were sick, and just simply take any medicine they have in the house. Especially antibiotics, analgesics, and asthma medications, these kinds of medicines …show more content…

During the embryonic period, the rate of cell differentiation intensifies, support system for the cells form, and organ appear. In week 3, an embryo, the person-to-be is just 1/10 of an inch (2mm) long. It has become elongated, and three layers emerge – the ectoderm, mesoderm, and endoderm. In week 4, the embryo is so curved that the two ends almost touch. The outer layer (ectoderm) folds into the neural tube. From the mesoderm, a tiny heart forms and begins to beat. The endoderm differentiates into a gastrointestinal tract and lungs. Between days 21 and 28, eyes develop. In the following week, ears, mouth, and throat take shape. Arm and leg buds appear. The handplate from which fingers will emerge appears. The heart divides into two regions, and the brain differentiates into forebrain, midbrain, and hindbrain. In week 6 and 7, the embryo is almost 1 inch long. The heart divides into four chambers. Fingers emerge from the handplate, and primitive facial features are evident. The important process of sexual differentiation begins. During the final week of embryonic period, most structures and organs are present. Ovaries and testes are evident. The embryo begins to straighten and assumes a more human appearance. Clearly, the embryonic period is dramatic and highly important because it is when the structures that make us human evolve. Yet most pregnant women, either because they do not yet know they are pregnant of do not appreciate

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