Prenatal Development and Birth Analysis - Research Paper Example

? Prenatal Development and Birth Introduction It is common knowledge that every human life begins as a single cell,formed when a male’s sperm fertilizes the female’s eggs. The development from a single cell into the full-grown child with so many organs and systems is a mystery to many. The development of a single fertilized egg into the human newborn infant with millions of cell and complex body systems in just 266 days is indeed a miracle. This kind of explosive growth and development rate is unparalleled in other stages of life. This paper discusses the prenatal development of human life detailing everything that goes on from conception to birth. The paper is structured in sections guided by the stages that occur in prenatal development: the germinal, the embryonic, and the fetal stage. In addition, the research will also look at the stages of birth. The Germinal Stage This is the earliest stage of human life from fertilization and extending for a period of two weeks (Gilbert, 2013). The term germinal is coined from the word germ. A germ cell refers to the male sperm and female egg cells (William, 2001). Life begins when the two germs fuse, in a process called fertilization. This process occurs naturally in fallopian tube if sperms are released into the vaginal canal during the fertile period of a woman usually through sexual intercourse. Advances in sciences have made it possible for fertilization to be done outside the woman body (IVF) and for human life to be fully developed in labs but this will not be covered in the present study. The germ cells carry the genetic information- DNA from each parent (Daniel, 2009). The sperm carries the Y chromosome, while the egg has X chromosome. The combination of the genetic material from the two reproductive cells provides a unique genetic blueprint for the each child (William, 2003). The Y chromosome contributes very little genetic information with the X chromosomes contributing to the entire mitochondrial information of the zygote (Daniel, 2009). However, the Y chromosome leads to the development of the male body type, through its SRY gene (Daniel, 2009). Fertilization results into a single cell called a zygote. For the next two weeks or so the zygote undergoes a lot of cell division and moves down the fallopian tube until it finally attaches itself to the uterine wall (implantation) marking the end of the germinal stage (William, 2001). About thirty-six hours from conception, the zygote, enters mitosis period, which is marked with rapid cell division plus duplication (William, 2001). At about 72 hours, the zygote has about 16 to 32 cells (William, 2003.). By the fourth day from fertilization, the zygote forms into a hollow fluid-filled ball of cell called a blastocyst. The cell division intensifies in the next number of days while, at the same time, the zygote moves down the fallopian tube towards the uterus. If separation of the blastocyst occurs at this period then twins are formed (Gilbert, 2013). The blastocyst takes 3 to 4 days down the fallopian tube after which it is freely floats in the uterus for a day or two then begins to implant. By now the blastocyst has already differentiated into two disk layers, the inner one that will form a new organism, and the outer which will provide a protective covering. Implantation starts to take place at around the seventh to the tenth day following fertilization and takes about a week to complete (Wilcox, Baird, & Weinberg, 1999). The outer layer of the blastocyst referred to as the trophoblast, which also produces hair-like structures. These hair-like structures are called villi, and they adhere onto the uterine wall, endometrium until the implantation of the blastocyst is complete. The Embryonic Phase The embryonic phase is the period beginning from implantation and lasting through the eighth week from fertilization (William, 2001). This period of around six weeks is marked with the most rapid prenatal development to form all major organs (Werth, & Tsiaras, 2002). This stage begins with the embryonic disk folding over into three cell layers: the ectoderm which will develop into the nervous system and the skin; the mesoderm, which will develop skeleton, muscles, circulatory system, and the other internal organs; and the endoderm which is to develop into lungs, the digestive system, urinary tract, and the glands. The development of the nervous system is rapid at the beginning of this period; a primitive spinal cord forms with the folding of the ectoderm (William, 2001). The other part of the blastocyst develops into the placenta, the umbilical cord, and the chorion. The chorion develops by the end of two weeks as a protective membrane around the amnion. The amnion encloses the embryo in a fluid called amniotic fluid, which serves as a cushion and temperature regulator. The placenta is to serve as a channel for food and oxygen to get to the zygote and for wastes products removal from the zygote. The umbilical cord, on the other hand, forms the connection between the placenta and the developing human. However, as high as thirty percent of the zygotes do not make it through this stage and termination of pregnancy occur (Keith, 2008). In the second month of pregnancy, rapid development of body parts and body systems continues and the embryo’s posture becomes more upright (Nilsson, 2006). At this point, the embryo can move, as well as respond to touch, especially around the mouth area and on the feet’s soles (Dudek & Fix, 2005). However, the embryo is very fragile at this stage and is susceptible to deformities from teratogens such as drugs, viruses, or radiation (Dudek & Fix, 2005). As the embryonic period ends, the embryo is only about an inch in length. The Fetal Phase This is the last stage of prenatal developmental, which lasts from the eighth all through up to birth. During this stage, the fetus grow to about twenty times bigger than its previous size while its organ and body system become more complex as they mature (Nilsson, 2006). The onset of the fetal phase is marked by the appearance of the first bone cells (Werth, & Tsiaras, 2002). From the third month of after fertilization, the nervous system, muscle, and organs organize and connect. By the twelfth week, external genitals have formed, and it is possible to detect the sex of the fetus through ultrasound. The head usually grows faster as compared to the organs of the body. By the end of the twelfth week, facial features are apparent though the skin is translucent and has no layer of fat (Gilbert, 2013). Fingernails also appear at around this time. The thirteenth to the twenty-fourth week forms the second trimester of pregnancy. By the middle of this trimester, the fetus is large enough such that the mother can feel its movements (Gilbert, 2013). The skeleton becomes visible, and the fetus resembles a human being though still tiny (Nilsson, 2006). A white cheese like substance develops to cover the skin and protect it from being chapped in the amniotic fluid (Gilbert, 2013). As the vernix form, fine white hair grows over the fetus’s body, which helps the vernix stick to the skin (Nilsson, 2006). Between the twentieth and twenty-second weeks, the heartbeat is hearable. By the twenty-fourth week, the fetus is ‘fully formed’ and all the major organs are functional, the digestive system and the lungs, however, still need more time to mature (England, Pritchard, & Hamilton1996). As the second trimester ends, the brains neurons have been produced, and the fetus can be irritated or stimulated by sound and light. The brains are usually the last organ to develop; most development takes place in the third trimester. During this period, the cerebral cortex becomes larger, and the fetus spends more time awake. By the thirty-second week, the head is more in proportion to the rest of the body; most fetus have their heads positioned down in the womb, and the eyes are open (Nilsson, 2006). By the thirty-sixth week, the hair covering the fetus disappears and fat is deposited under the skin to assist in temperature regulation. As the birth approaches, the fetus can barely move due to reduced space; the fetus further moves up in the ribcage causing shortness of breath and heartburn. The fetus is fully mature and with this kind of environment, the fetus can no longer sleep, birth is approaching. The stage of birth Naturally, the stage of birth occurs anywhere from the thirty-seven week to the fortieth during which the fetus is fully mature (Werth, & Tsiaras, 2002). However, it is also common for birth to take place anywhere after the thirty second week (Diane, Sally, & Ruth, 2004). Births occurring from the twentieth and thirty-seven week of pregnancy are termed to be preterm and if before the twentieth week then it is a miscarriage (MacCallum-Whitcomb, & Tharp, 2000). Birth involves several changes within the mother that allows the child to get out from the womb into the world. These contractions allow for cervix dilation (MacCallum-Whitcomb, & Tharp, 2000). These contractions, which are usually associated with pain on the mother, continue until the cervix has dilated to about ten centimeters (MacCallum-Whitcomb, & Tharp, 2000). The dilation is important to allow for the passage of the child’s head, which is the first part to come out under normal conditions. When sufficient dilation has taken place the child is descends into the birth canal and ultimately into the world usually through the facilitation of the mother who is encouraged to “push.” The child is now free to start life on its own; the umbilical cord is cut. Since, at this time, the child has fully functional body parts just like any other human being, it can live freely. The stage of birth is, however, not over until the placenta is also delivered. Where problems arise during delivery, delivery of the baby occurs through cesarean, in which delivery is facilitated through surgery. Sometimes the mother may as well ask for cesarean delivery with no complication at all. Conclusion The prenatal development of life is a complex process starting from fertilization. The kind of rapid growth and development described in this study is indeed the most explicit in the entire human life. After birth, there is no new organ or body system that develops on a person’ to add on the existing ones. We have also seen that most growth and development occur in the first two months within, which most organs in the human body are formed. The brain development develops the last beginning in the third trimester. References Daniel, S. (2009). "11-Development". Psychology Second Edition. United States of America: Worth Publishers Dudek, R. W., & Fix, J. D. (2005). Embryology. Philadelphia: Lippincott Williams & Wilkins England, M. A., Pritchard, S., & Hamilton, L. (1996). Life before birth. London: Mosby- Wolfe. Gilbert, S. F. (2013). Developmental biology. Sunderland, Massachusetts: Sinauer Associates Gould, S. (1997). Ontogeny and Phylogeny. Cambridge, Mass: Belknap Press Keith, M., L. (2008). Before We Are Born: Essentials of Embryology and Birth Defects. Philadelphia, PA: Saunders/Elsevier MacCallum-Whitcomb, S., & Tharp, J. A. (2000). This giving birth: Pregnancy and childbirth in American women's writing. Bowling Green, Ohio: Bowling Green State University Popular Press Nilsson, L. (2006). Life. New York: Abrams Werth, B., & Tsiaras, A. (2002). From conception to birth: A life unfolds. New York: Doubleday. Wilcox, A., Baird, D., & Weinberg, C. (1999).Time of implantation of the conceptus and loss of pregnancy. New England Journal of Medicine. 340(23), 1796-1799 William, J. (2001). Human embryology. Edinburgh: Churchill Livingstone Read More