Female Repro Function Flashcards
What are the two functions of the ovaries? Which specific hormones are made?
Produce and release ova; produce hormones (activin and inhibin)
What hormone is most active during the follicular phase? What is the one follicle that is chosen out of the cohort called?
FSH (stimulate follicle development) with rising estradiol from the follicles; primordial follicle!
Which hormone is most active during ovulatory phase? What happens during this phase?
LH surge; Graafian follicle ruptures and oocyte discharged
What happens during luteal phase? Which hormone predominates?
Ruptured follicle converted to the corpus luteum; LH, along with higher PROGESTERONE and some estradiol!
What is the ruptured follicle called? What will the corpus luteum degen to without fertilization?
corpus hemorrhagicum; corpus albicans due to low estrogen and progesterone
How many follicles become mature follicles? How many follicles ripen with each menstrual cycle?
ONLY ONE!! Several can ripen each menstrual cycle
What is synonymous with the term “chosen primordial follicle?” What cells can actually make estrogen? Why only them? What cells can provide the estrogen-producing cells the precursors? Where do these latter cells get the precursors from?
Graafian;
granulosa; They have aromatase
Theca cells (get cholesterol from LDL)
What does the primordial follicle contain? Size?
Ovum, granulosa and thecal cells; 30-60 micrometers
What happens during the proliferative phase? What hormone predominates and how long does this phase last approx?
Thickening the endometrium and priming uterus for progesterone actions;
estrogen
about 14 days (accounts for variable lengths of menstrual cycle)
What hormone dominates during secretory phase? What happens during said phase?
Progesterone; convert proliferative uterus to secretory one (more glandular secretions and increased vascularity)
How does estrogen prime the uterus for progesterone action?
It can increase the number of progesterone receptors on the uterus
What are the follicular and luteal phases synonymous with?
Proliferative and secretory (more or less)
What is the fixed length of the secretory phase?
14 days
Which cells have the FSH receptors? When do we see positive feedback on HP-ovarian axis? What hormones surge? What is provoked?
Granulosa; the late follicular and ovulatory phases;
FSH and LH
Ovulation
In ovulatory phase, what is producing hormones for feedback? What type of feedback do we see? What are the three hormones made? What is special about one of them?
Corpus luteum
Negative feedback
Estradiol, progesterone, inhibin
Inhibin only acts on the anterior pituitary to prevent release of FSH ONLY during luteal phase!!
What word defines LH secretion type?
Pulsatile
How do estrogens ultimately aid with producing a mid-cycle surge of LH (and FSH)?
They sensitize the anterior pituitary gonadotrophs to GnRH stimulation by increasing GnRH receptors, resulting in LH and FSH production and release
What does LH allow for mid-cycle?
Conversion of Graafian follicle to corpus luteum
Where does FSH bind to in the ovaries? What does this lead to?
Their receptors on granulosa cells; gene transcription an synthesis of relevant enzymes like aromatase, activins, and inhibins
Where does LH bind? What is made?
Their receptors on thecal cells and onto some receptors on granulosa cells; make progestins and androgens
How do androgens become estrogen?
Leave theca cells and enter granulosa cells
Where do activins and inhibins act? What does activin do?
ONLY ANTERIOR PITUITARY; activin has opposite activity of inhibin
How does GnRH exert its effects on gonadotropes?
GPCR, then IP3/DAG pathway (IP3 leads to IC Ca release, PKC leads to transcriptional reg), then creation and release of FSH and LH
What differentiates LH and FSH?
NOT the alpha subunits, rather their beta subunits!!
At the level of the anterior pituitary, what inhibits LH and FSH production/release, and what promotes that?
Follicular phase estrogen and activin promote; luteal phase estrogen, progesterone, and inhibin inhibit!!
What is the order of potency of estradiol relative to estrone and estriol?
Estradiol > estrone > estriol (10x and 80x respectively)
What do you need in granulosa cells to make estrogen? What is needed to get the androgen precursors in thecal cells?
Aromatase
17alpha-hydroxylase and 17,20 desmolase
What do steroid hormones bind to in serum?
Albumin and sex hormone-binding globulins (SHBG)
Where are estrogen and progesterone inactivated/degraded?
Former inactivated in liver through conjugation (excreted in urine); latter degraded in liver to steroids and excreted as above
What makes LDL available to granulosa-lutein cell?
Vascularization of corpus luteum
What is the major product of the follicle during the follicular phase? the major products of the corpus luteum during luteal phase?
Estradiol
Progestins (still substantial estradiol synthesis)
What can be produced by both theca-lutein and granulosa-lutein cells? What is made in theca cells that can’t be made in granulosa cells? What is made in granulosa cells that can’t be made in theca cells?
Progesterone;
17alpha-hydroxyprogesterone and androstenedione;
Estradiol
What do estrogens do?
Proliferation of endometrial stroma, mucosal lining development in fallopian tubes, bone growth (inhibit osteoclasts), and fat deposition in subcutaneous tissues
What does progesterone do?
Secretory changes in endometrium, less frequent/intense uterine contractions, more fallopian tube secretions; also lobules and alveoli development in breasts
Around which day will LH and FSH peak? What will also happen on this day?
14; ovulation
When does estrogen peak? What about inhibin and progesterone?
Right before ovulation to promote positive feedback; after ovulation
For puberty for females, what happens during thelarche? Adrenarche? Menarche?
Thelarche is breast development (11-15);
Adrenarche: increased secretion of adrenal androgens
Menarche: menstrual cycles begin (10-16)
When does the HP-gonadal axis become functional? When are gonadotroph cells most sensitive to negative feedback by estrogens?
Puberty;
Children; becomes less sensitive in puberty and even more so at adulthood
What is gone by menopause? What levels decrease? What levels increase?
Ovarian follicles
Sex steroids
Gonadotropins
What are characteristics of menopausal syndrome?
Vasomotor instability, hot flashes, night sweats, mood changes, short-term memory loss, sleep problems, headaches, loss of sex drive
What happens physically with menopause?
Vaginal epi atrophies, vaginal pH changes, vaginal secretions decrease, less blood to uterus and vagina, pelvic relaxation, vaginal tone lost, cardiovascular disease and osteoporosis risks increase
How many germ cells does a female at puberty have? How many are actually ovulated?
About 400000 (peak was once 6-7 million); 400 ovulated because of atresia of follicles that don’t become the primordial/Graafian one
What happens to LH and FSH levels as women get older?
Really high because you lose that negative feedback!
What is the increase in LH and FSH attributed to post-menopause?
Increased production (about 3-fold for LH, 17-fold for FSH)
What is a source of estrogen post-menopause? Where is it derived and produced?
Estrone
Derived from androstenedione in adrenal gland; produced in muscle and adipose
With decreased estrogen, what are women at risk for?
Osteoporosis and compression fractures in vertebrae (height loss, back pain, thoracic kyphosis/dowager’s hump)
