Regulation of Reproductive Hormones and Cycles

What is the function of Gonadotropin Releasing Hormone (GnRH)?

Promotes secretion of luteinizing hormone (LH) and Follicle Stimulating Hormone (FSH) in both XX and XY individuals.

Where is Gonadotropin Releasing Hormone (GnRH) produced?

Hypothalamus.

What is the target of Luteinizing Hormone (LH) in XX individuals?

Ovaries (follicle).

What is the target of Luteinizing Hormone (LH) in XY individuals?

Testis (Leydig cells).

What are the key roles of Luteinizing Hormone (LH) during the ovarian cycle in XX individuals?

Promotes follicle development (Day 0-12), triggers ovulation (Day 12-14), and supports corpus luteum development (Day 14-28).

What is the function of Follicle Stimulating Hormone (FSH) in XX individuals?

Promotes follicle development and ovulation.

What is the role of Follicle Stimulating Hormone (FSH) in XY individuals?

Promotes spermatogenesis in the testis.

What is the primary function of testosterone in XY individuals?

Promotes spermatogenesis and development of male secondary sex characteristics.

What is the source of estradiol in the female reproductive system?

Produced by the ovaries (follicle and corpus luteum).

What is the effect of estradiol on LH and FSH regulation?

Estradiol negatively regulates LH and FSH during early follicular phase and positively regulates them during late follicular phase.

What is the role of progesterone in the menstrual cycle?

Negatively regulates LH and FSH, and positively regulates growth of the endometrium.

What happens to progesterone levels if fertilization does not occur?

The corpus luteum degenerates, progesterone levels fall, allowing LH and FSH to increase.

What is the significance of the corpus luteum in the ovarian cycle?

It produces hormones and decays unless implantation occurs.

How are the uterine and ovarian cycles interconnected?

The ovarian cycle prepares the body for implantation of a fertilized egg during the uterine cycle.

What are the phases of the ovarian cycle?

Follicular phase and luteal phase.

What hormones are involved in the regulation of the ovarian cycle?

Gonadotropins (LH and FSH) and ovarian hormones (estradiol and progesterone).

What is the target of estradiol besides the anterior pituitary?

The endometrium (uterine lining).

What is the role of the seminal vesicles, prostate gland, and bulbourethral gland?

They contribute fluids to semen and support sperm function.

What is the primary oocyte's role in the ovarian cycle?

It develops into a secondary oocyte during ovulation.

What is the timing of GnRH pulses in XX individuals?

Most frequent during the follicular phase (menstruation).

What is the timing of GnRH pulses in XY individuals?

At regular intervals, with increased pulse length at puberty.

What is the role of inhibin in male reproductive regulation?

Inhibin negatively regulates FSH production.

What are the secondary sex characteristics promoted by testosterone?

Development of bones, muscles, and external genitalia.

What occurs during ovulation in the ovarian cycle?

The secondary oocyte is released from the ovary.

What happens to the endometrium during the ovarian cycle?

It thickens in response to estradiol and progesterone.