E. Placentation: 1. Refers to formation of the ("flat cake") that develops by the month. It is formed from the of the fetus and the of the mother's uterus. 2. FUNCTIONS: 1) It allows nutrients and On to diffuse from mom's blood to fetal blood, and CO, and wastes away. 2) It takes over the role of producing and estrogen, so the degenerates, and the ovaries become dormant for the duration of pregnancy. 3. The placenta detaches and sloughs off after the infant is born (" so the name of the maternal portion ( : "that which falls off") is appropriate. :the portion of the endometrium between the chorionic villi and the stratum basalis of the uterus. b) :part of endometrium surrounding uterine cavity side of implanted embryo. It expands to accommodate the fetus, which eventually fills and stretches the uterine cavity. 4. The fetal side of the placenta is slick and smooth, and the cord projects from its surface. The maternal side is bumpy due to the shape of the chorionic villus masses