PS102 Chapter Notes - Chapter 4: Phenylketonuria, Fetus, Miscarriage
Document Summary
Results in creation of single cell called a zygote. After the fourth day following conception, the zygote is now referred to as the blastocyst. About a week after fertilization, blastocyst implants itself to side of uterus. During the first 36 hours, the single cell zygote divides and becomes two cells. Cells keep multiplying as zygote moves through mother"s fallopian tube (where it was first fertilized) and to her uterus. Placenta allows circulatory system of mother to interact with circulatory system of embryo. Most major systems (nervous and circulatory, basic structure of body) begin to take shape. Systems formed but not fully developed or functional and cannot sustain life on their own. During the fetal stage, immature organ systems and structures continue to grow and develop. Lasts from end of embryonic stage until birth of baby. Pregnancy is naturally and spontaneously expelled from uterus before embryo or fetus is able to function on own.
