Final answer:
When estrogen levels rise outside of the cell due to follicular development, it indicates the follicular phase of the menstrual cycle. This phase is characterized by high estrogen production that activates a negative feedback loop to reduce FSH levels, leading to the atresia of most tertiary follicles, except for the dominant follicle which eventually ovulates.
Step-by-step explanation:
If the concentration of estrogen outside the cell rises in response to follicular development, it suggests a few key events in the menstrual cycle. The rise in estrogen typically indicates that the follicular phase is occurring, during which the granulosa and theca cells of tertiary follicles in the ovaries are responding to the hormone LH (Luteinizing Hormone), producing more estrogen. This elevated systemic plasma estrogen concentration engages a negative feedback loop that signals the hypothalamus and pituitary gland to reduce the secretion of GnRH (Gonadotropin-releasing hormone), LH, and FSH (Follicle-stimulating hormone).
As a result of these changes, most of the tertiary follicles undergo atresia, or cell death, due to the decreased levels of FSH which are necessary for their growth and survival. Nevertheless, typically one follicle, referred to as the dominant follicle, manages to survive and it becomes the sole follicle to release an oocyte during ovulation. Factors contributing to a follicle's dominance and survival include its size, number of granulosa cells, and the number of FSH receptors on those cells.