Development of the Human Embryo

To begin with, there is a certain arc of development for the entire organism, with a series of stages that can be determined and characterized as follows:

1. Immediately upon fertilization, cellular development begins.

2. At 20 days, the foundation of the entire nervous system has been laid down, including the beginning of brain development.

3. At 43 days, electrical brain wave patterns can be recorded, often seen as evidence that "thinking" is taking place in the brain.

4. At 56 days, all organs are functioningstomach, liver, kidney, brainand all systems are intact ("Chronology of a new human life," 1996, www.angelfire.com/ks/purplepandas/life.html).

Pregnancies are usually thought of in terms of trimesters, an easy division which also corresponds to developmental issues. The first trimester is a critical period in which most of the development of the various systems and organs is accomplished, with the brain appearing in

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ects of malnutrition at this stage are permanent. It exerts an influence not only during the brain-growth period but also during early organizational processes such as neurogenesis, cell migration, and differentiation. If malnutrition upsets the developing brain, the growth program of the organism can be severely damaged, with its dimensions replanned in an altered and somewhat distorted form (Morgane, Austin-LaFrance, Bronzino, Tonkiss, Diaz-Cintra, Cintra, Kemper, & Galler, 1993, 91-128). About 10 or 12 weeks after conception, the baby inside the womb is subject to an astonishing amount of sound as the nerve cells in the developing brain crackle with activity. This is long before there is any sensory input from the outside world. This activity is purposeful, with cells contacting other cells and creating pathways for the transmission of the huge amounts of information necessary for life. These messages are fired through the neurons, the long, wiry cells that carry electrical messages through the nervous system and the brain. They are not transmitting signals in scattershot fashion, for that would produce a featureless static. The evidence is growing, in fact, that the staccato bursts of electricity that form those disti
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Some common words found in the essay are:
Kemper Galler, Raven Johnson, , Bloom Lazerson, Berger-Sweeney Hohmann, Nash JM, Hohmann CF, Nowakowski RS, nervous system, Embryogenesis Chronology, Galler JR, brain development, development brain, brain cells, cortical development, neural tube, form neural, developing brain, human life 1996, human life, life 1996, tonkiss diaz-cintra cintra, birth baby's brain, chronology human life, austin-lafrance bronzino tonkiss,
Approximate Word count = 1603
Approximate Pages = 6 (250 words per page)

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