Breast Physiology Flashcards
Why does milk secretion begin at birth?
- Childbirth -> loss of placenta -> progesterone withdrawal
- Milk secretion requires withdrawal of progesterone and presence of PRL
Compare the role of PRL and oxytocin in lactation
PRL = milk production
Oxytocin = milk letdown
Describe how suckling affects milk production
- Suckling stimulus inhibits hypothalamic dopamine release
- This causes increased PRL pulses from anterior pituitary
- PRL causes milk production
Describe how suckling affects milk letdown
- Suckling causes increased release of oxytocin from posterior pituitary
- Oxytocin causes myoepithelial cells to squeeze milk glands
Where are PRL and oxytocin released from?
PRL released by anterior pituitary
Oxytocin released by posterior pituitary
Name 3 factors that inhibit milk production
- Stress
- Pituitary dysfunction
- Obesity
Why don’t breast-feeding mothers get pregnant?
PRL inhibits release of LH, FSH -> prevents ovulation
Name 2 cancer risks affected by breastfeeding
Breastfeeding decreases maternal risk of breast and ovarian cancer
Compare the two types of milk (4)
- Colosterol milk (focus on immunity)
- Watery
- High IgA, lactoferrin
- Low total volume
- Tight junctions are open
- Mature milk (focus on nutrition)
- Less IgA, lactoferrin
- High volume
- Tight junctions are closed
Are there cells in breast milk?
Yes! Breast milk contains macrophages and lymphocytes
Describe the symptoms of menopause.
HAVOCS
- Hot flashes
- Atrophy of the vagina
- Osteoporosis
- Cardiovascular disease
- Sleep changes
How do we define menopause?
What is the average age in the US?
Menopause = amenorrhea for 12 months
Occurs at ~51 yo
Describe the pathogenesis of menopause.
What would the hormonal levels be?
Decreased # ovarian follicles -> decreased estrogen production -> symptoms
Very high FSH, High LH, High GnRH, Low estrogen
Where does estrogen come from in post-menopausal women?
Peripheral conversion of androgens
