Puberty & HPG axis Flashcards
What age do females start puberty?
9-13 years old
What is the first sign of female puberty?
Breast buds (thelarche)
What age do males start puberty?
10-14 years old
What is the first sign of male puberty?
Genital development
What is the tanner scale?
Used to assess the stage of puberty
What causes epiphyseal plates to close?
Oestrogen
What is the critical weight for girls to start puberty?
47kg
What starts puberty?
Nocturnal release of pulsatile GnRH from the hypothalamus
How many peptide hormones does the anterior pituitary produce?
6
GnRH stimulates the anterior pituitary to produce what?
FSH and LH
How often is GnRH released?
Every 1-3 hours
What does LH do in males?
Stimulates Leydig cells to produce testosterone
Where are the Leydig cells in the testes?
In the interstitium around the seminiferous tubules
What do sertoli cells in the testes do?
Provide nutrition and hormonal support to germ cells to form sperm
Which cells in the female respond to FSH?
Granulosa cells
Which cells in the female respond to LH?
Theca cells
What is the feedback on GnRH in females?
Moderate oestrogen = negative feedback, High oestrogen = positive feedback (LH surge)
What does progesterone do to FSH and LH?
prevents positive feedback of high oestrogen preventing LH surge, increases inhibitory effect of moderate oestrogen. REDUCES GnRH, NO LH surge
What does Inhibin do to FSH?
Inhibits secretion
What does Leptin do?
It is the energy status of the bodies capability to maintain a pregnancy. Can regulate GnRH
