Female Reproductive Physiology pt.II

What is the primary feedback mechanism involved in the female HPG axis?

Negative Feedback

Low levels of estradiol trigger the hypothalamus to secrete more:

GnRH

The goal of increased GnRH secretion is to:

raise estradiol levels

Increased GnRH from the hypothalamus stimulates the anterior pituitary to release:

LH and FSH

Increased LH and FSH levels lead to increased production and release of

Estradiol

As estradiol levels rise, what happens to GnRH and LH/FSH levels?

They decrease

Which structure secretes GnRH?

Hypothalamus

Which structure secretes LH and FSH?

Anterior pituitary

Just prior to ovulation, the female HPG axis switches to..

Positive feedback

The switch to positive feedback occurs when there are:

High levels of estradiol

High levels of estradiol trigger the hypothalamus to release more:

GnRH

Increased GnRH causes an increase in:

LH and FSH

Increased LH and FSH stimulate additional release of:

Estradiol

Which hormone experiences the greatest surge before ovulation?

LH

The surge in LH and estradiol facilitates the release of the

Secondary oocyte

The release of the secondary oocyte from its follicle is called..

Ovulation

Just before ovulation, the female HPG axis switches from:

Negative to positive feedback

Prolonged exposure to high levels of estradiol causes the switch to positive feedback when estradiol levels are greater than:

300 pg/mL

High estradiol levels must persist for approximately how long to trigger positive feedback?

42 hours

High levels of estradiol increase the amount of:

Neural progesterone

Neural progesterone triggers the release of which hormone from the hypothalamus?

GnRH

Increased GnRH secretion stimulates the anterior pituitary to release more…

LH

Increased LH secretion causes the ovary to produce more:

Estradiol