Pregnancy Is Divided Into 3 Stages Essay
In the beginnings of a pregnancy the sperm fertilizes the ovum and it becomes a small mass of cells called a zygote. After about five days it develops into a grouping of cells called a blastocyst and becomes implanted in the uterine wall. It is in the first trimester that most of the major organ systems present themselves and the features are becoming recognizable as human. During the third and fourth weeks, the head undergoes a lot of development as the central nervous system begins to form, and the beginnings of eyes and ears are visible. By the end of the 10th week, the fetus’ eyes, ears, and extremities are completely formed. By the end of the 7th week, the internal organs have formed and have limited functionality. Although the genitalia have formed, the gender of the fetus is not quite distinguishable until week 12. From this point on, development consists mainly of growing larger and the differentiation of structures that are already present.
Not only is the fetus changing rapidly, but the woman is going through changes as well. Her hormone levels are changing, and her body is reacting to these hormones with changes to her breast tissue, her heart rate and even the shape of her body.
In the second trimester the baby’s skin is transparent and it has fine hair on its head called lanugo, and it starts to suck and swallow. Meconium is being made in the intestinal tract…