repro physiology Flashcards
levels of sexual dimorphism
genetic sex, gonadal sex, phenotypic sex
important genes in the Y chromosome
86 genes - impt is SRY (sex region Y) gene coding for TDF (testes determining factor) and also SOX9 (less important)
development of male genitalia
TDF activated at week 6 –> Sertoli cells produce Mullerian inhibiting substance –> Mullerian duct regression
TDF activated at week 6 –> Leydig cells produce testosterone –> Wolffian duct develops into male internal genitalia (vas deferens, seminal vesicles, epididymis, efferent ducts, ejaculatory ducts)
testosterone converted by 5α-reductase to DHT (dihydrotestosterone) –> development of male external genitalia (penis, scrotum, prostate gland, penile urethra, prostatic urethra)
important genes in female genital development
FOXL2, WNT4, FST (not that impt lah)
development of female genitalia
no Y chromosome –> no TDF –> no Leydig cells –> Wolffian duct regression
no Y chromosome –> no TDF –> no Sertoli cells –> no MIS –> Mullerian duct development –> female internal genitalia (uterus, fallopian tube, upper 2/3 of vagina)
ovary exists –> production of estradiol/estrogen –> female external genitalia (clitoris, labia minora, labia majora, lower 1/3 of vagina)
Turner syndrome cause and presentation
cause: X0 (only 1 X chromosome) - 1/2500 births
presentation:
• no gonadal development
• born phenotypically female
• underdeveloped gonadal structures –> little estrogen production –> poor breast development, no menstruation, infertile
• short stature, usually low IQ
Klinefelter’s syndrome cause and presentation
cause: XXY genotype - 1/700 births
presentation:
• normal testicular function + testosterone + MIS
• sexually underdeveloped due to extra chromosome
• infertile, small testes, decreased sperm production
• taller (insufficient testosterone –> late closure of growth plates)
• low IQ
Triple X syndrome cause and presentation
cause: XXX (non disjunction error)
presentation:
• normal physical development and no major medical problems
• decreased IQ
• risk of epileptic seizures
disorders causing true hermaphroditism
true hermaphroditism: gonadal tissue and germ cells of both sexes present
causes: XX (2/3 of patients), X0 / XY (1/3 of patients) due to mosaicism during gonadal development
disorders causing pseudohermaphroditism
pseudohermaphroditism: carries sex organs of one gender but looks like opposite gender
causes: androgen insensitivity syndrome, 5α-reductase deficiency
components of the female reproductive system
ovary, fallopian tube, vagina, uterus
describe the regulation of female sex hormones
GnRH (from hypothalamus) –> LH and FSH (from anterior pituitary)
LH –> testosterone (from theca cells) + estrogen and progesterone (from granulosa cells)
FSH –> estrogen and progesterone (from granulosa cells)
negative feedback inhibition of female sex hormones
estrogen inhibits anterior pituitary (FSH and LH) and inhibits hypothalamus (GnRH)
inhibin inhibits anterior pituitary (FSH and LH)
types of estrogen
E1: estrone
E2: estradiol (most reactive)
E3: estriol (supports pregnancy)
functions of estrogen
- development of ovaries, fallopian tubes, uterus, vagina, external genitalia
- secondary female sexual characteristics
- folliculogenesis
- lipid and protein metabolism (anabolic)
- libido
- stimulate bone growth
- inhibit lactation
- control menstrual cycle and maturation of sperm in men
- puberty
functions of progesterone
- promotes secretory changes in uterine endometrium
- reduce maternal immune response
- decrease contractility of uterine smooth muscle
- promotes development of lobules and alveoli of breasts
- inhibits lactation
- decreases libido
progress of folliculogenesis
primordial follicle - (enlarge) -> primary follicle - (zona pellucida, theca interna and externa) -> secondary follicle - (single fluid-filled antrum) -> Graafian follicle –> OVULATION: oocyte + corpus luteum -(degenerates)-> corpus albicaans
parts of the ovarian cycle
follicular phase, ovulation phase, luteal phase
parts of the uterine cycle
menstruation (7 days), proliferative phase (7 days), secretory phase (14 days)
hormone levels during the menstrual cycle
14: LH SURGE stimulating ovulation (FSH surge is smaller)
15-26: surge of estrogen first (inhibits FSH and LH with inhibin) by corpus luteum followed by progesterone surge, estrogen proliferates endometrium and progesterone maintains it, LH creates corpus luteum
27-28: decrease in estrogen and progesterone production by corpus luteum, endometrium starts to necrose
1-7: loss of negative feedback from estrogen causes increased FSH and LH, no progesterone = endometrium sheds
8-14: gradual increase in estrogen bc of FSH and LH causes endometrium proliferation, super high estrogen levels cause positive FSH and LH feedback and LH SURGE
changes during puberty in females
• at 9-12 yo
• thelarche, pubarche, menarche
• increased GnRH secretion by hypothalamus
changes during menopause in females
• 40-50yo
• ovulation fails to occur and menstrual cycle becomes irregular then ceases
• production of estrogen by ovaries decreases
• loss of estrogen: hot flushes, psychological and emotional changes, insomnia, breast/uterine/vaginal atrophy, increased risk of CVS disease and osteoporosis