Term
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Definition
-gonads are bipotential till 5 weeks
-in males, testes develop in 5-7 wks
-in females, ovaries develop at 9 wks
-genetic sex normally determines gonadal sex |
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Term
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Definition
-'sex determining region on Y' chromosome
-on non-pairing region of Y chromosome (no crossing over with x)
-normally, its' always retained on Y |
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Term
| What happens if SRY gene translocates to X chromosome? |
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Definition
-SRY from non pairing region translocates to X chromosome
-get X+sry sperm that fertilized X egg
-so get XX male, with underdeveloped testes |
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Term
| What happens is SRY gene is mutated or deleted? |
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Definition
-get XY female (called Swyer's)
-ovary can't make eggs, called a 'streak gonad' which docs tend to remove to avoid cancer
-lack of puberty |
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Term
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Definition
-germ cells=spermatogonia
-sertoli cells produce anti mullerian hormone (AMH)
-leydig cells produce testosterone |
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Term
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Definition
-germ cells=oogonia
-granulosa cells produce estradiol
-theca cells produce progesterone |
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Term
| Gonadal Sex determination of phenotype |
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Definition
-testes make AMH and testosterone first
-fetal ovaries do not secrete AMH
-without testes, fetus will default to being female |
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Term
| differentiation of male genitalia |
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Definition
-testosterone stimulates wolffian duct growth of epididymus, vas deferens, seminal vesicles, ejaculatory ducts
-AMH causes atrophy of mullerian ducts
-penis and scrotum differentiate at weeks 9-10 in presence of dihydrotestosterone (DHT) |
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Term
| differentiation of female genitalia |
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Definition
-in absense of testosterone, wolffian ducts regress
-in absence of AMH, mullerian ducts develop into fallopian tubes, uterus, upper 3rd of vagina
-in presence of estrogen, ext female genitalia develops (clitoris, labia, lower 2/3 of vagina) |
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Term
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Definition
| converts testosterone to dihydrotestosterone (DHT), which stimulates growth of penis and scrotum |
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Term
| When is fetus undifferentiated vs fully differentiated as male? |
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Definition
undiff at 5 weeks
diff as male at 12 weeks |
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Term
| Androgen insensitivity syndrome |
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Definition
-also called testicular feminization
-XY, but phenotypically female
-non menstruating
-blind ending vagina
-gynecomastia
-has testes, so makes AMH and get no development of uterus or fallopian tubes
-also makes testosterone but likely an 'androgen receptor defect' so don't get wolfian duct development or conversion to DHT, so end up with female external genitalia |
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Term
| congenital adrenal hyperplasia |
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Definition
-masculinzation of extermal female genitalia at birth
-normal uterus, fallopian tubes, ovaries
-menstruates at puberty
-XX with ovary so no AMH or testosterone
-but have active adrenal that causes masculinization of external genitalia (large clitoris, fused labia)
-caused by reduced negative feedback on hypo pit axis: poor levels of cortisol cause inc levels of ACTH which causes hyperplasia of cholesterol producing cells in adrenal cortex
-enzyme defect (21 hydroxylase deficiency) causes increased androgen production
-also have reduced aldosterone that causes salt wasting/dehydration |
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Term
| examples of genotype/phenotype discrepancies |
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Definition
-androgen insensitivity syndrome (testicular feminization)
-congenital adrenal hyperplasia
- |
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Term
| normal adrenal function and feedback |
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Definition
| -high levels of cortisol and/or aldosterone secreted from adrenal gland negatively feedback to hypothalamaic pit axis to inhibit ACTH |
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Term
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Definition
-GnRH pulses
Before puberty:
minimal to no GnRH release so low levels of FSH, LH, estrogen, testosterone
-minimal to no folliculogenesis, spermatogenesis
After puberty:
-inc in pulse freq and amp of GnRH release
-inc FSH, LH pulses
-inc estrogen and testosterone
-get folliculogenesis and spermatogenesis |
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Term
| levels of FSH and LH across female life span |
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Definition
-have spurts during development between 1st trimester and 6 mo./1 yr
-then negligible levels in childhood, rise at puberty, then very high in menopause
-in puberty, see relatively constant level of FSH and cycles of LH |
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Term
| male versus female puberty |
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Definition
FEMALE
-breast bud
-pubic hair
-peak growth spurt
-ovulation after peak height
-menarche
-adult pubic hair and breasts
MALE:
-genital development
-pubic hair
-spermatogenesis then peak height
-genitalia and pubic hair adult |
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Term
| main driver of puberty in boys? |
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Definition
-activation of hypothalamic pituitary -hypo pit axis increases leydig cell synthesis and secretion of testosterone
-causes spermatogenesis, penile growth, pubic hair, voice lowering
-growth spurt culminating in closure of epiphyses (hand and wrist commonly used to assess growth) |
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Term
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Definition
GONADARCHE:
-hypo pit axis drives ovarian estradiol synthesis from granulosa cells
-causes breast bud, linear growth spurt, menarche
ADRENARCHE:
-inc production and secretion of adrenal androgens
-may occurs as early as 2-3 years before puberty onset
-causes axillary hair and pubic hair growth |
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Term
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Definition
| used to assess stage of puberty |
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Term
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Definition
-eventually produce gametes
-are precusors to oogonia and spermatogonia
-start in hindgut of embryo and move to gonads where multiply |
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Term
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Definition
| completes meiosis I at ovulation |
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Term
| secondary oocyte completes meiosis at fertilization |
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Definition
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Term
| key events in ovarian cycle |
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Definition
-follicular growth
-ovulation
-ovary secretes estradiol (E2) and inhibin
-luteal function
-corpus luteum secretes progesterone and estradiol
-luteal regression |
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Term
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Definition
-multiplication of granulosa cells
-development of antrum
-growth of oocyte |
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Term
| What are granulosa and theca cells stimulated by? |
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Definition
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Term
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Definition
granulosa cells that surround oocyte and zona pellucida (non cellular glycoprotein coat)
-note there are cytoplasmic bridges from cumulus to oocyte for transport |
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Term
| How is estradiol production controlled? |
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Definition
-FSH induces granulosa cells to aromatize androgens prouduced by theca cells...estradiol is product of this (happens with aromatase)
-granulosa cells also make inhibin which decreases FSH |
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Term
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Definition
-made by granulosa cells
-FSH stimulates the secretion of inhibin from the granulosa cells of the ovarian follicles in the ovaries. In turn, inhibin suppresses FSH.
-inhibits FSH production and GnRH release from the hypothalamus
-diminished by GnRH
-stimulated by IGF-1 |
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Term
| How is dominant follicle selected? |
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Definition
it has most FSH receptors
-insufficient FSH causes atresia |
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Term
| describe levels of FSH and LH during follicular phase |
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Definition
are low, suppressed by neg feedback of estradiol (causes proliferation of endometrium) on ant pit
-during follicular phase, FSH and LH receptors are upregulated in both theca and granulosa cells |
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Term
| How does estradiol cause preovulatory LH surge? |
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Definition
-usually estradiol causes neg feedback
-but when E2 levels are maintained high for long enough, causes positive feedback to ant pit... becomes more sensitive to GnRH, causing LH surge |
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Term
| How does LH surge affect follicle? |
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Definition
-oocyte:auses completion of meiosis I, extrusion of polar body. oocyte arrested in meiosis II
-microvilli across zona pellucida are withdrawn
-loosening of cumulus cells
-at ovulation, there is enzyme/prostaglandin induction in follicle wall |
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Term
| transformation of ruptured follicle to corpus luteum |
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Definition
-theca cells and blood vessels invade
-granulosa cells hypertrophy and terminally differentiate (luteinization)
-ruptured follicle becomes solid corpus luteum
-steroid secretion changes: now secretes progesterone and estradiol |
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Term
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Definition
-enhances proteolytic enzymes
-digest and rupture follicle wall |
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Term
| What happens to cervical mucous during ovulation |
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Definition
| increases in quantity and becomes less viscous so sperm can penetrate |
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Term
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Definition
| terminal differentation of stromal cells in uterus, in order to prep for pregnancy |
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Term
| What is optimal time for implantation? |
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Definition
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Term
| What is corups luteum formed from? |
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Definition
| from luteinized granulosa and theca cells of dominant follicle |
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Term
| Why does basal body temp increase in luteal phase? |
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Definition
| progesterone affects hypothalamic thermoregulatory center |
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Term
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Definition
-only about 60 ml
-can lead to signifcant loss of iron/anemia |
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Term
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Definition
-stimulate follicle development
-induces aromatase activity in granulosa cells to make estradiol from androgens
-induces formation of LH receptors
-selection of dominant follicle |
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Term
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Definition
-produce androgens in theca cells
-stimulates last stages of follicular development
-induces ovulation
-stimulates formation of corpus luteum |
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Term
| where does fertilization take place |
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Definition
| ampulla of fallopian tube |
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Term
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Definition
-blastocyst hatches from zona pellucida
-appostion to receptive endometrium (decidualization)
-invasion of trophoblast
-corpus luteum maintained by hCG from syncytium
-if no implantation, CL degenerates |
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Term
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Definition
-placenta makes all pregnancy hormones
-needs cholesterol from mother and fetal adrenal gland to convert progesterone (pregnenolone) to DHEA-Sulfate. placenta needs 17 alpha hydroxylase from fetal adrenal.
-pregnenolone (shunted to adrenal gland where converted to DHEA-S to 16 OH DHEAS in fetus this is shunted back to placenta where it's converted to estriol |
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