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45 Cards in this Set

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Functional unit of the ovary
Follicle
Impt 3 features of the follicle and their functions?
1)thecal cells - steroid hormone synthesis
2)granulosa cells - synthsize steroids and nourish the ovum
3) oocyte - female gamete
What are the 3 principal hormones secreted by the ovary?
estradiol, progesterone and androstenedione
What are the 3 types of estrogen and which is the strongest?
estradiol (most potent), etsrone (in post-menopause)and estriol (made a lot during pregnancy?
What does aromatase do and where is it located?
Aromatase converts testosterone to estradiol and Androstenedion to estrone
and is found in the granulosa cell
E3 is
estriol and drived from degradtion of E1 and E2
E1 is
estrone and derived from estradiol and aromatization of androstenedione
E2 is
Estradiol and is the most potent and made by the ovary
Fcn of 17-B-hyroxysteroid DH
converts estrone to estradiol
What is the major product of the granulosa cell?
estradiol
Which thecal layer is more vascular?
thecal inner and gets cholesterol for steroid syn. from LDL
What 2 cells are impt in estrogen syn?
interstitial cells of the theca interna & ovarian stroma AND granulosa cells
What regulates the theca cells?
LH
What regulates granulosa cells
fsh
What is the principal product of theca cells
androstenedione
Principal source of progesterone
Corpus luteum
Describe the circulating hormones during the lifetime of a woman
1) up to 6mon - High FSH/low LH
2)childhood - 0 to very low
3)puberty -beg to increase and may see a surge.
4)14-50 (repro years) - more LH/less FSH. cyclic release of Gonadatrophins and interrupted if preg occurs
5)post 50 - more FSH and less LH ( due to decrease in GnRH)
What mechanism is used by LH/FSH
cAMP
Net effect of theca cells vs granulosa cells?
theca cells are androgen biosynthesis while granulosa is estrogen biosynthesis
Which molecule is 18 C steroid
estrogen + it has an aromatic ring
Which molecule is a 21 C steroid?
progestin
Which proteins are bound to estrogens?
Sex hormone binding globulin (SHBG)
Which proteins bind to progestin?
corticosteroid-binding globulin (CBG) and albumin
what 2 organs are involved with menses
ovary and uterus
What receptors are expressed on granulosa cells
estrogen, androgens and FSH
what receptors are expressed on thecal/interstitial cells
LH
T/F Follicular growth from the primoridal follicle to the pre-antral follicle requires gonadotrophin?
FALSE, it does not
How does the dominant follicle grow?
First, it inhibits the development of other follicles by decreasing FSH which forces others to go through atresia. Then it upregulates FSH receptors and stimulates growth factors such as IGF-2. inhibin and activin
Does FSH upregulate LH receptors on granulosa cells?
yes, it does and and it may be a protective function. Also, the dominate follicle can accumulate FSH in its follicular fluid (atretic follicles do not have FSH)
what is atresia
form of apoptosis
T/F FSH has anti-apoptotic genes
true
factors to promote atresia
TNF alpha, androgens and IL-6
signal for ovulation
LH surge
LH surge is result of?
+feedback of estradiol on pituitary/hypothalamus
what are the 3 effects of LH on the pre-ovulatory follicle?
resumes meiosis, ovulation and lutenization of the follicle
what 2 proteins are required by ovulation and are induced by LH?
1)progesterone receptor which activates proteases to digest the follicle wall
2)COX-2 -Prostoglandin (PG) formation from arachidonic acid which helps to promote ovulation
what is OMI
oocyte maturation inhibiting substance - LH thought to suppress this so meiosis can re-start
T/F Corpus albicans promotes implantation of the ovum
FALSE, it is corpus luteum
what controls progesterone in the corpus luteum?
LH
what occurs if pregnancy doesn't occur
c luteum becomes corpus albicans
how does estradiol favor luteolysis (break down of corpus luteum)
1) feedback inh of LH
2) local effects by PGF2alpha
what are the different stages of follicular development
primordial germ cells, primordial follicles (where meiosis stops), primary follicle, secondrary follicle, pre-ovulatory follicle OR recruitment, selection, early dominance, late dom/maturation
significance of Intraovarian signals
primordial follicles stimulated to leave the resting pool
length of time from primordial follicle to pre-ovulatotory follicle
85 days
at which stage would one consider a DOMINANT follicle to be in?
mid-follicular ( right around ovulation)