Male/Female Reproductive Cycles

Which cycle consists of the ovarian cycle (in the ovary) and the menstrual cycle (involves uterus)?

female reproductive cycle

What are the 3 phases of the menstrual cycle?

1. proliferative

2. secretory

3. menstrual flow

What event starts menstruation?

disintegration of

the endometrium

(Note: menstrual

flow phase)

Which brain areas initiate the menstrual cycle?

hypothalamus and

anterior pituitary

Which hormone levels do the hypothalamus and anterior pituitary monitor in the menstrual cycle?

estrogen and progesterone

Low levels of estrogen and progesterone cause what response in the brain?

hypothalamus to secrete GnRH

GnRH secretion by the hypothalamus causes what response in the anterior pituitary?

release FSH and LH

What hormone stimulates the follicle to secrete lots of estrogen?

FSH

(Note: positive feedback

with hypothalamus)

Estrogen produced by the follicle causes what response in the hypothalamus?

produce GnRH

The estrogen-initiated production of GnRH in the hypothalamus mid-cycle causes what response in the anterior pituitary?

LH surge

Which hormonal event triggers ovulation

LH surge

By the time of the LH surge, what structure has the follicle developed into?

corpus luteum

By which hormone is the corpus luteum developed and maintained?

LH

After ovulation, which hormones decrease?

LH and estrogen

Which hormones does the corpus luteum secrete?

estrogen and

progesterone

The secretion of estrogen and progesterone by the corpus luteum stimulate the development of which membrane?

endometrium

How does the endometrium develop in response to estrogen and progesterone release?

thickens in preparation

for implantation of

fertilized egg

If there is no implantation of a fertilized egg, what occurs in the hypothalamus?

low GnRH production

from increased estrogen

and progesterone

If no implantation occurs what effect does the low GnRH production from the hypothalamus have on the anterior pituitary?

terminates FSH and

LH production

If no implantation, what effect does low FSH and LH have on the corpus luteum?

disintegrates and

becomes corpus

albicans

If no implantation, what effect does the zero secretion of estrogen and progesterone from the corpus albicans have on the endometrium?

endometrium sheds

(Note: back to

menstrual flow phase!)

If implantation occurs, what hormone does the embryo (placenta) secrete?

human chorionic gonadotropin (HCG)

What effect does HCG have on the corpus luteum?

maintains the corpus luteum

The maintaining of the corpus luteum has what effect on estrogen and progesterone levels?

the levels remain high

(Note: endometrium not shed)

After implantation, HCG is replaced by which hormone produced by the placenta?

progesterone

The follicle that releases the secondary oocyte is also called what?

Graafian follicle

What are the 3 phases of the ovarian cycle?

1. follicular phase

2. ovulation

3. luteal phase

Which phase of the ovarian cycle includes the development

of egg and secretion of estrogen from follicle?

follicular phase

(Note: ends at ovulation)

Which phase of the ovarian cycle includes the mid-cycle release of egg?

ovulation

Which phase of the ovarian cycle includes the secretion of estrogen and progesterone from the corpus luteum?

luteal phase

How long does the shedding of the uterine lining approximately last?

5 days

The luteal phase of the ovarian cycle overlaps with which phase of the menstrual cycle?

secretory phase

Which hormone serves to thicken the endometrium?

estrogen

Which hormone serves to develop and maintain the endometrial wall?

progesterone

Which hormone inhibits lactation during pregnancy?

progesterone

(Note: fall in progesterone

after delivery allows for

milk production)

In the male reproductive cycle, GnRH stimulates the production of which hormones?

FSH and LH

(Note: LH in male

reproductive cycle

is AKA interstitial cell

stimulating hormone (ICSH))

LH stimulates the testes to produce which hormones?

testosterone and

androgens

(Note: promote

spermatogenesis)

Which hormones influence Sertoli cells to promote the development of sperm?

FSH and testosterone

How often does hormone and gamete production occur in the male reproductive cycle?

constantly

LH stimulates which cells to release testosterone and androgens?

Leydig cells

(Note: in the

interstitium between

seminiferous tubules)

Sertoli cells secrete what hormone to act on the anterior pituitary and inhibit FSH secretion?

inhibin

Which hormones can be increased in females to serve as a contraceptive?

estradiol or progesterone

How do artificially spiked estradiol or progesterone inhibit pregnancy?

suppresses LH/FSH surge so no ovulation can occur

Which hormones can be decreased in males to decrease sperm production as a contraceptive?

LH and FSH