Puberty and Menopause + Breast function and breast as a target organ for hormones

what is the onset of puberty for girls and boys?

• girls → 10-14

• boys → 12-16

what 4 things control the onset of puberty?

• secretion of GnRH

• Sex hormones

• Adrenal androgen secretion (increase of 17a-hydroxylase)

• Leptin

what are the three stages of puberty in girls?

• Thelarche: breast buds

• Pubarche: axillary/pubic hair

• Menarche: period

which tanner stage does peak growth happen?

girls → 3

boys → 4

difference between Precocious pseudo puberty (peripheral) and Precocious true puberty (Central)?

peripheral involves development of characteristics with no sperm/ovum production meanwhile central means early but normal puberty due to early secretion of GnRH

name one syndrome that causes peripheral precocious pseudopuberty?

McCune-Albright syndrome

• cafe-au-lai spots

• due to a mutation in GNAS gene → stimulation of adenylate cyclase → overproduction of hormones

what is classified as pathologically delayed puberty and what is the main cause?

• cause: CDGP

• girls → no period by 17

• boys → no testicular development by 20

two causes of absent puberty?

• turner syndrome → xo

• Eunuchism

how long can perimenopausal phase last?

7-10 years+

caused by decrease of AMH

name symptoms of menopause?

• hot flashes

• obesity

• fatigue

• mood swings

• bad sleep

• vaginal dryness + painful intercourse

main treatment for menopause?

low doses of HRT involving estradiol

what are the two functions of estradiol in relation to the breast?

• growth of ductal system

• adipose tissue accumulation

what are the cyclical changes in adult breast tissue?

proliferative → proliferation of mammary glands

secretory → progesterone makes lobules + alveoli growth

what is the effect of prolactin on breast tissue in pregnancy?

causes acini to make polyamines which are necessary in breast milk production

why is milk not produced even though they are developed by 10-12 weeks of pregnancy?

prolactin cannot bind because progesterone is taking its place

when is colostrum produced?

by 16 weeks

difference between fat and protein content in human milk vs human colostrum

fat is higher in milk

protein is higher in colostrum

how is prolactin regulated?

HPA control by dopamine

-ve feedback by high prolactin

+ve feedback by oestrogen + lactation

how is milk initiated?

progesterone drops and prolactin surges, if no breastfeeding by day 3-4, no milk ever is produced

ovulation is suppressed while breastfeeding

why is lactation not a valid contraception method?

LH & FSH are still produced in the ovarian cycle

function of oxytocin?

secreted from hypothalamus

causes contraction of myoepithelial cells and milk ejection

what are the causes of gynecomastia?

increased oestrogen: androgen ratio in newborns due to mother, teens due to puberty, and adults due to cirrhosis/hyperthyroidism