female reproductive Flashcards
1
Q
define GnRH
A
- acts on ant pit to release gonadotropins
2
Q
define LH
A
act on ovary to increase estrogen/progesterone/inhibins
3
Q
define FSH
A
- act on ovary to increase estrogen/progesterone/inhibins
4
Q
define estrogen
A
- increases size of uterus, ovaries, vagina, breasts
- causes proliferation of endometrial stroma lining
- inhibits osteoblast activity
- increaes body protein and fat deposition
- increases sodium and water retention
- makes mucous thin and stringy which can help guide sperm
5
Q
define progesterone
A
- promotes secretory changes of uterus, and prepares uterus for implantation
- decreases uterine contractions
- decreases prostaglandin production
- secretes fluid in fallopian tubes
- increases secretory development of breast tissue
- opposite effect on cervical mucous (increases viscosity)
6
Q
describe the cell types and regulatory signals involved during steroidogenesis
A
- GnRH released in pusatile fashion 5-25 mins every 1-2 hours
- results in LH release around eery 90mins
- estrogen rises during follicular phase and peaks before dropping off at luteal phase
- progesterone rises during luteal phase and drops off at end.
7
Q
describe estrogen role in the follicular phase
A
- estrogen exerts a negative feedback regulation primarily at the level of the anterior pituitary and to some extent the hypothalamus
8
Q
Describe estrogens role at mid-cycle (just prior to ovulation)
A
- 36 hours of relatively high estrogen concentrations exert a POSITIVE FEEDBACK at the level of the anterior pituitary and to some extent the hypothalamus resulting in a gonadotropin surge
9
Q
describe progesterone and estrogens role at luteal phase
A
- progesterone and estrogen exert NEGATIVE feedback at the level of anterior pituitary and to some extend the hypothalamus
- result of neg. feedback is gonadotopin production declines which results in decline of steroid production
10
Q
describe Inhibin B roles in the female sexual cycle
A
- inhibin B is secreted by granuloma cells and exerts a negative feedback on anterior pituitary FSH secretion
- Just after ovulation, Inhibin B spikes to decrease FSH secretion
11
Q
describe inhibin A role in female sexual cycle
A
- inhibin A is high in the luteal phase and acts on the ant. pit. to inhibit gonadotropin secretion
12
Q
describe the transition to pregnancy
A
- If implantation occurs, the corpus luteum does NOT regress
- Instead, the placenta releases hCG
- hCG stimualtes ovarian steroidogenesis by binding to same LH receptor (becasue LH is decreasing during this time)
- Corpus luteum secretes relaxin to inhibit myometrial contractions
13
Q
describe the changes that occured after week 8
A
- the placenta can synthesize steroids and corpus luteum is no longer needed
- progesterone suppresses uterine contractions, inhibits prostaglandin production and impacts immune response
- estrogen stimulates uterine growth, thickens vaginal epithelium and growth/development of mammary epithelium
14
Q
describe key hormone changes observed during puberty
A
- pusatile release of GnRH at night between 8-13 years
- increase in estrogen synthesis and female development begins to take place
- menses begins around 13 years which indicates estrogen levels are high enough for endometrial growth
15
Q
describe key hormone changes observed during menopause
A
- beings around age 36 and symptoms of follicle loss begin around 51
- decrease in follicles results in decline of estradiol and inhibin causing a loss of negative feedback and elevated LH/FSH
- extragonadal estrogen exists, however huge decline in estrogen production = hot flashes, night sweats, loss of libido, loss of bone mass, increased risk of heart disease
16
Q
describe the two phases of ovarian cycle
A
- Follicular phase (day 1) is characterized by follicle development, endometrial proliferation
- follicular phase is followed by ovulation
- Luteal phase occurs after ovulation and characterized by corpus luteum formation, endometrial differentiation
- followed by menses
17
Q
describe steroid production in follicular phase
A
- estradiol production during follicular phase is regulated by the gonadotropins
- -> theca cells synthesize androstenedione in response to LH
- -> androstenedione is converted to estradiol in granulosa cells which is controlled by FSH
18
Q
describe follicular phase
A
- rise of gonadotropins with a particular emphasis on FSH increase
- granulosa cell proliferation causes secretion of follicular fluid (hormones)
- development of theca cells which forms a capsule around follicle and produce hormones
- Increase in steroid production (estradiol) regulated by LH and FSH
- extremely rapid follicle growth under control of steroids and gonadroptropins
19
Q
describe the regulation of rapid follicular growth
A
- Estradiol increases expression of FSH receptors resulting in increased granulosa cell sensitivity to FSH and more follicular secretion
- Estradiol and FSH increased expression of LH receptors on theca cells further increasing follicular secretion
- Rise in estradiol from the ovary and ris in LH from the anterior pituitary induce proliferation of the thecal cells resulting in an increase in follicular secretion
20
Q
describe the endometrial growth in follicular phase
A
- proliferation of uterine endometrium is regulated by estrogen
- -> proliferation of epithelial cells (4-7 days for complete)
- -> proliferation of stromal cells
- -> growth of endometrial glands
- -> blood vessel development
- -> mucus secretion
21
Q
describe ovulation
A
- Day 14, ovulation is stimulated by a surge of LH (required) and FSH
- LH stimulates rupture of the follicle by promoting a remodeling of the follicle through changes in gene expression patterns and cell signaling events
22
Q
describe the temperature changes during ovulation
A
- Basal body tempature (BBT) is the body temp at rest
- typically taken after waking up from 6 or more hours of sleep
- Progesterone is thermogenic and produces .5-.8 degree increase in BBT
- monitoring BBT can be used as an indicator of ovulation
23
Q
describe the corpus luteum
A
- corpus luteum forms during the luteal phase
- forms from thecal, granulosa, fibroblast, endothelial, and immune cells as well as lipids
- -> temporary endocrine gland and secretes estradiol and progesterone
- corpus luteum reaches a mature state around 7-8 days following ovulation
24
Q
describe steroid production in luteal phase
A
- Increases in estradiol and progesterone production during luteal phase
- -> luteinized theca cells synthesize androstenedione in response to LH
- -> androstenedione is converted to estradiol in the luteninized granulosa cells which is controled by LH
- Also there is an upregulation of genes required for progesterone synthesis also under the control of LH
25
Q
describe the endometrial differentiation in luteal phase
A
- during luteal phase, differentiation and secretory development of uterine endometrium is regulated primarily by progesterone
- Key endometrial changes:
- -> increased complexity of vascular and glandular structures
- -> accumualtion of substances in glands
- -> deposition of lipids and glycogen in stromal cells
- -> increased blood supply
26
Q
describe the negative feedback mechanism in luteal phase
A
- rise in steroids (progesterone and inhibins (inhibin A) exert negative feedback at the level of anterior pituitary
- as a result gonadotropin production declines which results in decline of steroid production
27
Q
define involution
A
- twelve days following ovulation the corpus luteum begins to regress (involution) and becomes corpus albicans
- steroid production decliens with regression of corpus luteum
28
Q
describe menstrual phase
A
- declines in estrogen and progesterone production results in:
- -> the release of proteolytic enzymes that cause lysis of tissue
- -> increase of prostaglandin production that increases myometrial contractions
- with the decrease in gonadal steroid production, negative feedback inhibiton on the HPG axis is relieved and gonadotropin (LH, FSH) production begins to rise
