Question

Before complex development of a fetus can begin, implantation into the uterine wall must occur. What gets implanted in the uterine wall?

A.
a solid ball of undifferentiated cells called a morula
B.
a zygote consisting of only a single cell
C.
a blastocyst containing some differentiated cells
D.
an egg that has not yet been fertilized by a sperm

Answer 1

implantation consists of three stages: (a) the blastocyst contacts the implantation site of the endometrium (apposition); (b) trophoblast cells of the blastocyst attach to the receptive endometrial epithelium (adhesion), and (c) invasive trophoblast cells cross the endometrial epithelial basement membrane and invade ..