NEET BIOLOGY

Detailed explanation-1: -About 5 to 6 days after the sperm fertilizes the egg, the fertilized egg (zygote) has become a multicelled blastocyst. A blastocyst (BLAS-tuh-sist) is about the size of a pinhead, and it’s a hollow ball of cells with fluid inside. The blastocyst burrows itself into the lining of the uterus, called the endometrium.

Detailed explanation-2: -Implantation. Once the embryo reaches the blastocyst stage, approximately five to six days after fertilization, it hatches out of its zona pellucida and begins the process of implantation in the uterus.

Detailed explanation-3: -Uterus: the uterus is a hollow, pear-shaped organ with thick muscular walls. The normal length of the uterus is about 8cm. The uterine cavity is lined with mucosa that allows the implantation of the embryo. This endometrium develops each month during menstruation and until ovulation.