NEET BIOLOGY

Detailed explanation-1: -Sperm can fertilize the egg in the zona pellucida (ZP), which prevents the fertilized egg, called a zygote, from adhering to the wall of the fallopian tube. If the zygote implants in any area besides the uterus, the result is an ectopic pregnancy.

Detailed explanation-2: -Chemical pregnancy – A chemical pregnancy occurs when the fertilized egg doesn’t implant or fails to develop after implantation. This may cause you to miss your period and can even result in a positive pregnancy test. However, when you go for an ultrasound, your doctor won’t be able to detect the pregnancy.

Detailed explanation-3: -The event which does not occur during implantation is that-the embryo does not secretes enzymes that digest away part of the endometrium.

Detailed explanation-4: -The lining of the uterus is receptive to the embryo for only a brief time, called the Window of Implantation. It is possible that a perfectly normal embryo might not implant because the lining was not ready for it. In natural cycles, the window may be 4-5d wide, but in our treatments in can be only 12-48h long.

Detailed explanation-5: -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.