PS275 Chapter Notes - Chapter 4: Embryonic Disc, Prenatal Development, Universal Windows Platform Apps
Document Summary
Just because a risk or benefit is associated with a certain behaviour doesn"t meant that engaging in the behaviour will ensure that outcome. From conception to birth: development begins in the fallopian tube when a sperm penetrates the wall of an ovum, forming a zygote, from the moment of conception, it will take appx. The period of the zygote: blastocyst name given to the ball of cells formed when the fertilized egg first begins to divide, contains 60-80 cells within 4 days of conception, cell differentiation has begun. Inner layer of the blastocysts (embryonic disk) becomes the embryo: the outer layer of cells will develop into tissues that protect and nourish the embryo. Inner layer endoderm becomes the digestive system, lungs, urinary tract, and other vital organs, such as the pancreas and liver. If the embryo is a male, a gene on its y chromosome triggers a biochemical reaction that instructs the indifferent gonad to produce testes.
