The New Year never fails to rein in an eclectic range of resolutions, from the life changing to the downright dumbfounding; nevertheless these feats are attempted in the hope o development. Whether wishful thinking or willpower is permeating 2013’s endeavors, commendable personal development has already been achieved and all before the initial breathe – embryonic development. Details have historically been disputed over what goes into making a Homo sapien; from Aristotle proposing fathers dominantly contributed to their offspring’s characters being disproved be Harvey’s Exercitationes de Generatione Animalum stating it was in fact the egg from which the being came. Even the concept that the whole human form had always existed in a miniature form and grew throughout life was believed by preformationism. With the sequencing of the human genome, increased understanding of its molecular basis, the field of epigenetics as well as developmental biology, processes and theories have been cleared up; both males and females contribute to the characters of their offspring.
Embryonic development retains a certain level of compelling mystery and the beauty of its complexity validates analysis:
Cleavage follows fertilisation, in which the cells divide, increasing in mass with little growth; resulting in overall size not increasing. These cells are totipotent, able to become any cell type within the body, making these stem cells incredibly significant. As time progresses, the cells the cells fate slowly become more and more committed to a particular fate. Embryonic stem cells have the ability to revolutionise both understanding of processes as well as new medication and gene therapies, on the other hand the use of growing human embryonic stem cells strictly for experimental purposes are controversial, leading to great ethical dispute.
After this the vital stage of gastrulation takes place; cell movement establishes three fundamental layers of cells: the ectoderm giving rise to parts such as the skin and nervous system, the mesoderm giving rise to parts such as muscle and bone, and the endoderm giving rise to parts such as the gut, lungs and pancreas.
Simultaneously, a number of other processes take place, for example: axis are determined such as back to front and head to toe, the nervous system is established in neurulation and segmentation is also established; while very vivid in insects, humans to have segmentation in terms of the like of arms and legs made during limb formation.
Overall a single cell has increased fifty trillion fold; so whether finding the cakes to tempting to cut out, losing a battle to procrastination or concluding that the freezing January temperatures are far too grueling a concept to attend that gym session, take comfort in our prenatal conquest.
Image reproduced from php.med.unsw.edu.au and bio1151.nicerweb.com
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