Kinesiology 3347A/B Chapter Notes - Chapter 4: Epicanthic Fold, Fetal Alcohol Spectrum Disorder, Philtrum
5 Apr 2017
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Both genetic and extrinsic factors combine to influence growth and aging. Patterns in growth and aging: universality: patterns that hold for all humans, specificity: individual variation. Implantation: hundreds of cells by the time the blastocyst has implanted on the uterine wall due to cleavage. Abnormal prenatal development: source of abnormal development can be genetic or extrinsic, congenital defects (present at birth) can derive from a genetic or extrinsic source. Placenta acts as a barrier to harmful substances, but cannot protect against these teratogens. Fetal alcohol syndrome: ~1 in every 1000 births, characteristics, small eye openings, smooth philtrum (between lip and nose, thin upper lip. Extrinsic causes of abnormal development (continued: development of the maternal blood supply to the placenta is complete by ~12- 13 weeks: placenta screens some substances (ex: large viruses) but not teratogens, tissues undergoing rapid development at time of exposure are most vulnerable.
