implanted in the lining of the women uterus. When a female is pregnant she will go through an orderly sequence that takes her through stages as the soon to be baby begins to grow. The term prenatal development is broken down into three periods which are called the germinal, embryonic and the last is the fetal. Once the soon to baby is fertilized the egg will carry all of its genetic information to create a new organism, and that is when the mother begins to go into the beginning stages …show more content…
The embryonic period starts right after the implantation in finally complete. The book understand human development states the embryonic period “ is a time of major structural development and growth that continues until two months after conception”(68). During this time period cells that are forming into the supporting structure they begin forming a placenta, umbilical cord and an amniotic sac. The placenta is a disk-shaped mass of supporting tissue, the umbilical cord is a rope of tissue that contains two arteries, and the amniotic sac is a membrane filled with water amniotic fluid that helps cushion and protect the baby throughout the prenatal period. All though all three of the supporting structures are important, but the placenta is mainly the most important. The placenta provides the exchange of waste and nutrients between the mother and embryo. The mother and embryo don’t share the same blood, which is the make reason for placenta. Understanding Human Development states “the placenta permits the exchange of nutritive and waste materials by diffusion across cell membranes, normally without any exchange of blood cells. Thus, the placenta serve as a filter”(68). At the end of this prenatal period all of the human structures should there. The structures include arms. Legs, eyes, fingers, heart, brain and all major organs. The digestive and excretory systems are forming at …show more content…
The fetal period starts around the third month of pregnancy to the birth of the child. During the fetal period the soon to be baby 's organs and systems will began to mature and start to become functional. Many of the organs and systems will mature and become more functional during the fetal period. During the fourth month of pregnancy is when the fetuses hearts begins to start beating fasting, its teeth and bones become more dense, finger and toenails are fully developed and lanugo starts to cover the baby’s body. At the end of the fourth month the baby should weigh around five ounce. After the four month the fetus will develop senses of taste and smell, start getting their eyelashes and eyebrows, and the fetus will even start moving around the mother stomach. According to Clevelandclinc.org “The baby 's skin is covered with a whitish coating called vernix caseosa. This "cheesy" substance is thought to protect baby 's skin from the long exposure to the amniotic fluid. This coating is shed just before birth.” When the fifth month is complete the baby should weigh from eight ounces to a pound. On the six month of pregnancy the fetus’s eyes are completely formed and their organs begin to shift into the correct places. During this point the of pregnancy the baby starts to develop primitive brain waves, which they didn’t have until this moment. The baby’s brain also