Development, Anatomy, and Physiology of Breast Flashcards
Process by which breast develops
mammogenesis
Process by which milk is produced
lactogenesis
Primary function of mammary gland is ___
lactation
Functions of mother’s milk
nourishment, passive immunity, mother/child bonding, postpartum uterine involution
The outflow area which marks the coming together of breast glands is the ____
nipple
Breast lobule
specialized acinar alveolar cells produce milk and pump it into the ducts
Pigmented area around the nipple
areola
Blood supply to breast
2/3 internal mammary, 1/3 lateral thoracic
Lymphatic supply to breast
3% internal mammary, mostly axillary nodes
2 tissue components of breast
epithelial (20%) and stromal (80%)
Epithelial component of breast
ducts (luminal epithelia and myoepithelia) and lobules (alveolar epithelia)
Stromal component of breast
fibrous connective tissue (fibroblasts) and adipose (adipocytes)
TDLU
terminal ductal lobular unit –> outpouchings lined with alveolar cells
_____ stroma is cellular compared to ____ stroma
intralobular vs interlobular
Hormonal requirement for breast devleopment. Puberty:
estrogen –> ductal morphogenesis(elongation)
Hormonal requirement for breast devleopment. Pregnancy:
progesterone and prolactin –> lobuloalveolar development
Hormonal requirement for breast devleopment. Lactation:
prolactin (cortisol) and insulin in absence of estrogen/progesterone
Which stage of breast development is hormone independent?
early fetal development of milk streak –> mammary bud –> primordial ductal tree
Which stage of breast development is dependent on parental/placental sex steroids?
late fetal development involving canalization of ducts and parenchymal differentiation —> colostrum formation
T/F breast undergoes cyclic changes in response to hormonal fluctuations of menstrual cycle
T
Mitotic rate of glandular epithelial cells of breast is greates during ___ stage
luteal –> E2 + P is more mitogenic than E2 alone
Breast changes during luteal phase
volume, nodularity, sensitivity due to tissue edema and hyperemia NOT due to the epithelial changes in the breast during luteal stage
Progesterone and estrogens inhibit lactogenic action of ____
prolactin
Terminal differentiation of alveolar epithelial cells occurs during ____
lactation –> high prolactin levels in setting of low E2/P
dopamine agonists like _____ inhibit lactogenesis
bromocriptine
neural reflex arcs involved in milk production/ejection
nursing –> oxytocin –> myoepithelial contraction + suckling –> prolactin –> milk production = transcription of milk genes, induction of enzymes for lactose synthesis, induction of differentiation
Requirements for continued lactation
regular removal of milk, intact hpa axis, adequate diet and nutrition
T/F ovaries required for nursing
F
Lactation induced amenorrhea
hyperprolactinemia induce inhibition of gonadotropin secretion
Postlactational involution
at waning, prolactin and oxytocin release not stimulated –> unremoved milk leads to increased acinar pressure –> lactation ceases within 7-10 days
During postlactational involution, 80% of epithelium dies by ____
apoptosis
Involution take ____ months and involves remodeling of tissues
3-4 months –> partiy leads to a permanent change in breast
Hypoplasia/amastia
asymmetry common, underdevelopment uncommon –> secondary to biopsy, chest wall trauma, thoracic radiation in childhood
Supernumerary nipples/polypastia
secondary to incomplete regression of milk streak
Galactorrhea
persistent discharge of milk in absence of parturition; discharge in non-nursing mother > 6 months postpartum
Diff Dx: Galactorrhea with hyperprolactinemia and amenorrhea
prolactinoma or drugs
Dx: galactorrhea with normal prolacin and regular menses
excessive sensitivity of breast to prolactin
Sheehan’s Syndrom
infarction of pituitary during labor and delivery –> prone to decreased blood flow due to increased size during pregnancy
Lack of postpartum milk production may be the first sign of ___
Sheehan’s Syndrome
Breast cancer risk: older age of menarche
increases risk
Breast cancer risk: older age at menopause
increases risk
Breast cancer risk: ovariectomy
reduces risk
Breast cancer risk: postmenopausal obesity
increases risk
Breast cancer risk:early first full term pregnancy
reduces risk