Answer
Six days after fertilization the floatin blastocyst attaches to or implants into the endometrium of the uterus. Site of implantation is usually in posterior or central area part of the uterus. The orientation of the blastocyst is with the inner cell mass facing the endometrium. On the seventh day after fertilization, the attachment becomes stronger as the endometrium responds. The adjoining endometrial gland enlarge, the endometrium becomes more vascular. The blastocyst now secretes enzymes and burrows into the endometrium.
Work Step by Step
The hydrolytic enzymes secreted by the blastocyst clears a way for it to bury itself into the uterine endometrium. The endometrium responds by completely surrounding the blastocyst.
