Final answer:
During the proliferative phase of the menstrual cycle, the endometrial lining is rebuilt, with the epithelium being renewed under the influence of rising estrogen levels produced by the tertiary follicles. This estrogen also prompts changes within the blood vessels and endometrial glands.option b is correct.
Step-by-step explanation:
Proliferative Phase of the Menstrual Cycle
During the proliferative phase of the menstrual cycle, the endometrium undergoes several changes. Primarily, this phase is characterized by the rebuilding of the endometrial lining which had been shed during menstruation. The proliferative phase is driven by rising levels of estrogen produced by the granulosa and theca cells of the tertiary follicles.
The stratum functionalis of the endometrium—also known as the functional layer—is the part that thickens during this phase. This increased estrogen concentration prompts the renewal of the epithelium, making it the correct answer for the changes observed in the proliferative phase. Other noteworthy changes during this phase include the proliferation of blood vessels and the glands of the endometrium becoming more prominent and possibly coiled, in preparation for potential implantation of a fertilized egg.
Understanding the roles of estrogen in this process is crucial, as it orchestrates the endometrial preparation for a possible pregnancy. If an embryo does not implant, the corpus luteum degenerates, and this result in the shedding of the endometrial layer during menstruation, marking the cyclic nature of the menstrual cycle.