Hormones Flashcards
Where does the anterior pituitary arise from in development?
Rathke’s pouch
What type of gland is the anterior pituitary?
Endocrine
What type of tissue is the posterior pituitary?
Nervous tissue
How is GnRH secreted?
In a pulsatile fashion
What does testosterone do to the HPA?
negative feedback
What does oestrogen at intermediate concentrations do to HPA?
negative feedback
What does progesterone do to HPA?
negative feedback
What does oestrogen at high concentrations do to HPA?
stimulates it for a LH surge
What does the hypothalamus secrete?
GnRH
What does the anterior pituitary secrete?
LH and FSH
What does LH do?
Stimulates Leydig cells to release testosterone
Stimulates Theca cells to secrete oestrogen (androgens then converted to oestrogen by granulosa cells)
What does FSH do?
Stimulates granulosa cells to develop graafian follicles and ovulation by oestrogen
Stimulates Sertoli cells to produce spermatogenesis
What stimulates ovulation?
LH surge
What is LH’s role after ovulation?
stimulates corpus luteum to secrete progesterone and oestrogen
What does prolactin do?
Inhibits ovulation
What are the actions of testosterone?
Behaviour - sex and aggression
Maintenance of male internal genitalia
Metabolic effects
Why is there a waiting phase?
Because conceptus is too small to signal is presence so body assumes it’s pregnant until it knows 14 days later
What are oestrogens effects in the follicular phase?
Muscular contractions in the fallopian tube Stimulate growth and motility Thickened endometrium Thin, cervical mucous Depress appetite Calcium metabolism
What are oestrogens effects in the luteal phase ?
reduced fallopian tube motility further thickening of myometrium thick, acidic mucous catabolic change basal body temp mammary tissue changes
What triggers apoptosis of corpus luteum?
fall in oestrogen and progesterone
endometrium collapses
apoptotic cell death
shred as a menstrual bleed, spiral arteries contract to reduce bleeding
Why is oestrogen, progesterone and inhibin low in follicular phase?
no theca
What controls the reproductive cycle?
Pelvic clock
