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Steroidogenesis

this is what "rules the roost" in keeping a woman fertile; controls ovulation and folliculogenesis

Ovulation

this event occurs at day 14 of the menstrual cycle

Menses

this event occurs on days 0-4 (normally) of the menstrual cycle

Primordial Follicle

this follicle is part of the nongrowing ovarian follicular reserve; the types of follicles woman we born with

Primary Follicle

this follicle is in the first stage of growth; it is growing and getting ready

Dominant/Preovulatory (Graafian) Follicle

this follicle is quite large; contains a subpopulation of cells that makes hormones and growth factors

Theca Cells

this outer layer of the preovulatory follicle has CYP17 and therefore makes androgens (progesterone, androstenedione, testosterone); respond to LH

Granulosa Cells

this inner layer of the preovulatory follicle has CYP19 and therefore makes estrone, estradiol, and progesterone; respond to FSH and later LH (in response to FSH stimulation)

DHEAS

this is a stabilized form of DHEA with sulfur on it; released from the adrenal and can be used by ovarian follicles as a substrate to make E2; can be used as a marker

CYP19

this is aromatase; makes E2 from testosterone

CYP17

this cytochrome makes cortisol and androgens in the adrenal cortex

CYP11A

this is 20,22-desmolase / CYP450 side chain cleavage; forms pregnenalone from cholesterol

Corpus Luteum

this is the remnant of the follicle after ovulation; secretes a large amount of progesterone from theca cells and progesterone and E2 from granulosa cells

Primordial, Primary, and Preantral Follicles

these have very low (almost negligible) levels of androgens, testosterone, progesterone, and E2

Preovulatory/Dominant/Graafian Follicle

in this type of follicle, androgen production increases heavily in theca cells while E2 production increases heavily in granulosa cells

StAR

this transporter sends cholesterol to the mitochondria from theca cells; allows it to be converted to pregnenalone and then into androgens; mutated in CAH

Androstenedione

this androgen precursor can be made into testosterone; secreted heavily by theca cells upon LH stimulation

Preovulatory Granulosa Cells

uses androstenedione from theca cells to make testosterone which is then converted by CYP19 to make E2; mediated by FSH

Granulosa Lutein Cells

these granulosa cells respond to LH; major product is progesterone with E2 being a minor product

Growing Cohorts

a group of follicles that is recruited each month to grow and get ready from which one will be selected

Preovulatory FSH Surge

this surge in FSH occurs right before ovulation

Inhibin B

this acts on gonadotropes in the pituitary to suppress FSH and activin; works with E2 to decrease FSH during the mid follicular phase

E2 During Mid Follicular Phase

at this time, this hormone is at low levels but blocks FSH secretion at the level of the GnRH pulse generator

E2 During PreOvulatory Phase

at this time, this hormone increases in strength and now stimulates FHS secretion and inhibits inhibin production to free activin so that FSH can be released

FSH in Luteal Phase

at this time after ovulation, this hormone decreases because of negative feedback from inhibin A, increased levels of P4, and E2

Follicular Phase

this is the proliferative phase of the menstrual cycle; it includes the events leading up to ovulation including the preovulatory gonadotropin surge and slowly increasing levels of E2 and P4

Luteal Phase

this is the secretory phase of the menstrual cycle; it includes the events after ovulation including elevated P4 and E2 that slowly declines up until the point of menses

LH at Midfollicular Phase

unlike FSH, this hormone is purely regulated by hormone feedback (rather than inhibins and activin); at this phase, low levels of E2 are providing negative feedback

LH at Preovulatory Phase

at this phase, this hormone is stimulated by rising levels of E2; occurs just prior to its surge, which is extremely powerful

LH at Luteal Phase

at this phase, this hormone is drops in concentration due to elevated P4 and E2

Progesterone (P4)

this hormone is negligible during the follicular phase but then shoots up during the luteal phase because it is created by the corpus luteum

Basal Body Temperature

this rise in temperature can be used to see if a woman is ovulating; occurs because P4 is thermogenic, so it increases temperature after it is released during ovulation

P4R

these receptors are expressed in the hypothalamus where the GnRH pulse generator is; this allows it to block the pulse frequency and thus stop LH (preferentially) and FSH secretion, blocking fertility and menstruation

Progestin Contraceptives

these introduce P4 into the body exogenously, allowing for a sustained elevated P4 level, causing LH and FSH secretion to be blocked by messing up the pulse generator and blocking fertility

E2 During the Menstrual Cycle

this hormone begins to rise in the midfollicular phase, and then drops slightly at the luteal phase only to level off and be sustained by the corpus luteum following the drop

ER-Alpha

this receptor for this hormone is found in the hypothalamus where it messes up the GnRH pulse frequency and blocks FSH (preferentially) and LH secretion

Sustained Levels

if this occurs with either GnRH, LH, FSH, or the androgens, it causes a lack of fertility; levels must be cyclic for fertility to occur

Hyperandrogenemia

this is a problem that occurs when the body receives too many androgens; androgens are converted to E2 via CYP19, and thus the pulse frequency of GnRH can be affected, blocking FSH (preferentially) and LH secretion

Infertility

this is clinically defined as the inability to conceive after one year of unprotected sex

Primary Infertility

this type of fertility occurs when a woman is G0P0 and cannot conceive

Secondary Infertility

this type of infertility occurs when a woman is G1P1 or more but cannot currently conceive

Inhibin B

this acts on gonadotropes of the anterior pituitary to decrease secretion of GnRH and FSH; leads to atresia of nonselected follicles; in ovary, allows for steoidogenesis and production of growth factors

Activin

stimulates FSH secretion to stimulate growth of young recreuited follicles; promotes E2 production and LH receptor expression via FSH; blocked by inhibin B

Gonadotropin Surge

this is the surge of LH and FSH before ovulation, with LH being secreted in much larger amounts

Endometrial Proliferation and Angiogenesis

this change in the endometrium occurs at the time of ovulation due to rising levels of E2 and P4

Endometrial Shedding, Menstruation, and Repair

this change in the endometrium occurs in the late luteal phase due to sustained high levels of progesterone, causing decreased amounts of PR and ER-alpha receptors, no longer allowing E2 or P4 to work on it

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