PSY 335 Chapter Notes - Chapter 3: Amniotic Sac, Ejaculation, Fetus
9 Sep 2014
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Aristotle: epigenesis - the idea that there is an emergence of new structures and functions during development. Results form the union of 2 gametes - egg & sperm. Male releases 40 million - 1. 2 billion sperm per ejaculation - more than 500 billion in lifetime. 120-150 males are conceived for every 100 females because the sperm with y chromosome are lighter and swim faster to the egg than those with an x. Male embryos are miscarried at a higher rate than female. Boys are more vulnerable to developmental disorders and illness. Cell division results in the proliferation of cells. Cell migration is the movement of cells from their point of origin to somewhere else in embryo. Cell differentiation transforms the embryo"s unspecialized stem cells into different types of cells. Apoptosis, genetically programmed cell death, also enables prenatal development. Hormones play a crucial role in sex differentiation based on presence or absence of testosterone.
