If fertilization occurs, into which layer of the uterus does the fertilized egg (zygote) typically implant?

• A. Perimetrium
• B. Cervical mucosa
• C. Myometrium
• D. Endometrium

Answer: (D)

Verified step by step guidance

1. Understand the structure of the uterus: The uterus has three main layers—Perimetrium (outermost layer), Myometrium (middle muscular layer), and Endometrium (innermost layer). The Endometrium is the layer that undergoes cyclical changes during the menstrual cycle to prepare for potential implantation.
2. Recognize the role of the Endometrium: During the menstrual cycle, the Endometrium thickens and becomes highly vascularized under the influence of hormones like estrogen and progesterone. This prepares it to support a fertilized egg (zygote) if implantation occurs.
3. Learn the process of implantation: After fertilization, the zygote travels through the fallopian tube to the uterus. It then attaches to the Endometrium, which provides nutrients and support for the developing embryo.
4. Eliminate incorrect options: The Perimetrium is the outer protective layer and does not support implantation. The Cervical mucosa is part of the cervix and is unrelated to implantation. The Myometrium is the muscular layer responsible for contractions but does not play a direct role in implantation.
5. Conclude that the correct answer is the Endometrium, as it is the layer specifically designed to support the implantation and development of the fertilized egg.