development of the human Essay

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Development from Conception to Birth
Suleima Godinez
PSY 235
Dr. Schultz

When a woman becomes pregnant, her body becomes invaded by something so tiny that brings big changes. She begins to feel symptoms such as nausea, unexplained tiredness, tenderness in breasts and lots more. There are three periods that the pregnancy is divided into: germinal, embryonic, and fetal. Throughout these periods major developments happen with the “baby”. The fetus starts developing and growing until it is time to be born, while the soon-to-be mother is taking care of her body by eating more nutrients, avoiding things that can damage the fetus’s development and start prenatal visits to ensure that everything is on a good start. The soon-to-be mother also needs to start taking prenatal vitamins that has folic acid, because it will decrease the possibilities of birth defects.
Major Periods and Developments of Pregnancy During the first 14 days, there is a process that happens once the sperm and the egg have successfully joined. The zygote starts traveling down the fallopian tube to the uterus and the cells also starts multiplying. The cells start separating into two masses, the outer cells becomes a shell that is called the placenta and the inner cells become the embryo. After that has happened, the outer cells reach the implantation on the maternal uterine walls and begins the next stage. This first stage of the pregnancy is called the germinal period. The second stage is the embryonic period, “the embryo begins to develop the primitive streak which becomes the neural tube 22 days after conception and eventually developing into the central nervous system, the brain, and the spinal column.” (p.94, The Developing Person through Childhood)
The embryonic stage is the most amazing part of human life, how every part of the embryo starts falling in place. At the beginning of the fourth week the heart starts to pump, the head starts to appear as well as the eyes, nose and mouth. On the fifth week, buds starts to emerge that eventually becomes the arms and legs. This takes place from the third through the eighth week and at the eighth week the embryo weighs approximately one-thirteenth of an ounce. “The upper arms and then forearms, palms, and webbed fingers grow. The legs, knees, feet, and webbed toes in that order, are apparent a few days later, each having the beginning of a skeletal structure.” (p.95, The Developing Person through Childhood) By the end of the first trimester, the soon-to-be mother has a greater chance to see the sex of the baby through an ultrasound or sonogram. In the second trimester, the fetus starts to develop the digestive system and the excretory systems; also, the fingernails, toenails, buds for teeth, and hair starts to grow. Crucial brain development also occurs during the middle three months; up to half a million brain cells per minute are developed during this time.
“The reason brain growth is critical at this point is that the entire central nervous system becomes responsive during mid-pregnancy, beginning to regulate basic body functions such as breathing and sucking.” (p.97, The Developing Person through Childhood)
At the end of the third trimester, the fetus’s lungs begin to expand and contract, the heart’s valves go through final maturation, as well as the arteries and veins throughout the body. The weight of the fetus is very important in the development; at the end of the first trimester the fetus should weigh 3 ounces. At the second trimester the fetus weighs approximately 2-3 lbs. and when a full-term baby is born it should weigh around 7 ½ lbs. When the baby is ready to be born, the brain signal the release of hormones, specifically oxytocin, and starts labor. Throughout the process of labor there are a few stages that needs to happen for it to be a normal, uncomplicated birth. “The first stage of labor: The cervix dilates to