Reproductive endocrinology Flashcards
What are Leydig cells?
testis cells
what are sertioli cells?
testis cells
What do Leydig cells do?
form testosterone (lipid soluble - released as soon as it s made) LH activates enzymes- stimulate rate limiting step in production
What do Sertoli cells do?
receptor for FSH= expression of androgens receptor (AR)
testosterone binds= turn on androgen related gene producing enzyme (5aR)5a reductase
This enzyme reduces testosterone into dihydrotestosterone
How is dihydrotestosterone suited to its function ?
higher affinity than testosterone
needed for the production of male reproduction organs before birth
Whats does dihydrotestosterone and testosterone cause ?
spermatogenesis + masculinization
What does testosterone do (5)?
Increase muscle mass + bone density
Androgen effect Activates genes in Sertoli cells
drives mitosis of spermatogonial stem cells + meiosis entry
Lowers GnRH (hypothal) -ve feedback
Lower FSH + LH release from anterior pituitary -ve feedback
What are Thecal and Granulosa cells ?
Ovarian cells
Whats the most potent oestrogen
17 beta estradiol
what do Thecal cells do?
They’re LH receptors. When LH binds it turns on expression of cholesterol desmolase + 17-a-hydroxylase = produce androtestosterone + testosterone
Whats the function of Granulosa cells?
FSH receptor (converts Ando + testosterone into estrogen)
what does 17beta-estradiol do?
Stimulates:
- growth of uterus
- division of granulose cells in follicles
- granulosa cells to take up FSH receptor= more 17b-estradiol (+ve feedback)
- lowers GnRH
- lowers FSH +LH production from anterior pituitary
What causes ovulation?
Surge of LH
End of follicular phase due to sudden change in hypo to + feedback of GnRH release
What happens during ovulation?
Surge of LH
LH (+ FSH) increase
Dominant follicle ruptures
Release oocyte into reprod tract
Whats the hormone of pregnancy?
Progesterone
What happens in the Luteal phase?
Formation of Corpus Luteum (produce progesterone)
What stops a 2nd follicle forming ?
Low FSH
what blocks a second ovulation?
low LH
What is the myometrium in the uterus ?
muscle layer
Whats the endometrium in the uterus ?
inner stromal + lining epithelia cell
What are the four cell types in an embryo?
Syncytiotrophoblast(makes hCG) + cytotrophoblast(form placenta )
Hypoblast (form yolk sac)
Epiblast (form embryo)
What does hCG do?
PREVENT CORPUS LUTEUM DEGRADING
binds to LH receptors
What does Luteolysis mean?
NOT pregnant
cell death of corpus lute cells = progesterone drops, FSH increases
What does progesterone do?
- block follicle development + ovulation
- cervical plug (block mircoorgs)
- keep myometrium
- breast tissue growth
- made by placenta in later stages of pregnancy (luteoplacenta shift)
what is parturition dependent on?🤰
HORMONES
