I. The embryonic period, which begins during the second week of pregnancy and concludes at the end of the eighth week, is regarded as the most dramatic phase because all the major organs of the body are formed during this time and the growing organism develops from a cluster of cells into a very complex embryo that is clearly identifiable as human. The fetal period follows the embryonic stage and is marked by rapid growth and development of the structures that were formed in the embryonic stage.

Very few new organs appear during this stage and the fetus essentially prepares for birth and survival and hence this stage is known as ‘growth and finishing phase. ‘ II. The brain begins to develop about 18 days after fertilization and as the different parts of the brain develop, they mediate fetal behavior that is essential for prenatal development. The hindbrain and the brain stem are the first parts to develop and by 9th week of gestation the fetus will display spontaneous movements governed by the brain stem.

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The brain stem further matures to form the medulla, pons and mid-brain. The medulla mediates arousal, breathing, heart rate, and gross movement of the body. Pons and mid-brain develop later and mediate body movements and reactions to sound. III. I would choose the following environmental influences because: a. Maternal nutrition – Nutrition is arguably the most important factor that promotes healthy prenatal development.

Thirty million underweight babies are born annually and the WHO believes that poor nutritional status of women during pregnancy has a negative impact on the mother’s health as well as on the birth weight and early development of the child. b. Avoid Alcohol – Alcohol is the most common drug abused by pregnant women and even moderate amounts of alcohol can cause fetal alcohol syndrome characterized by small head, abnormal facial appearance, growth retardation and learning disabilities. c.

Be aware of prescription drugs – Exposure to antibiotics like tetracycline can cause yellow staining of teeth and diminished bone growth. Exposure to anticoagulant Warfarin can cause mental retardation. IV. Several studies have suggested that neonates born to mothers who have used epidural analgesia during labor may perform poorly on Brazelton Scale of behavior on the first day and although, the behavior improves by the fifth day, medicated babies continue to exhibit poor organization skills.

In addition, mothers who did not take the drug reported their babies to be more sociable and easy to care for, and these mothers were more responsive to their babies’s cries. The negative affect of epidural analgesia clearly demonstrates the bidirectional influences as stated by the Ecological Systems Theory. The mother’s choice of the medication makes the newborn unresponsive and poorly organized. This unresponsive behavior of the child prevents the parent from bonding to the child and as a result parent may also become less responsive to their baby’s needs.