Question

Select the positive feedback example:

a) Body temperature adjusting during ovulation
b) estrogen secretion after ovulation
c) luteinizing hormone triggering ovulation

Answer 1

The positive feedback example in the menstrual cycle is the LH surge that triggers ovulation, which is stimulated by high estrogen levels produced by the dominant follicle.

Step-by-step explanation:

Positive Feedback in Hormonal Regulation

In the context of the menstrual cycle, a classic example of positive feedback occurs during the ovulation phase. When the dominant follicle secretes increasingly high levels of estrogen, this does not lead to the expected negative feedback to reduce hormone release. Instead, the antecedent high estrogen levels trigger a switch in the anterior pituitary gland, leading to a significant release of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH). This surge in LH and FSH in the bloodstream is what leads to ovulation—the release of an oocyte from the dominant follicle.

The LH surge that triggers ovulation is a classic positive feedback example, as it amplifies the response (high estrogen levels result in higher LH release), contrary to maintaining homeostasis. LH and FSH play critical roles in this process; specifically, the LH surge induced by the elevated estrogen production from the dominant follicle stimulates ovulation, which in turn marks the end of the follicular phase of the menstrual cycle and the beginning of the luteal phase.