B8.035 The Breast Flashcards
basic anatomy of the normal breast
6-10 major ductal systems originate at the nipple
successive branching of the large ducts eventually leads to the terminal duct lobular unit (TDLU)
TDLU histology
functional secretory unit
ducts and lobules are lined by an inner ductal epithelium and an outer myoepithelial layer
basal lamina of type 4 collagen and laminin is present outside of the myoepithelial cell layer and serves to demarcate the breast TDLU from the surrounding stroma
interlobular stroma
dense fibroconnective tissue admixed with adipose tissue
intralobular stroma
closely surrounds TDLU
loose, delicate, myxomatous stroma
hormonally responsive
contains scattered lymphocytes
prepubertal breast in both males and females
large duct system ends in terminal ducts with minimal lobule formation
male breast development
T induces the involution of the duct system
no TDLUs develop
normal female breast at menarche
terminal ducts five rise to lobules
interlobular stroma increases in volume
E stimulates the development of ducts (in the presence of prolactin)
P stimulates the formation of lobules
normal breast during follicular phase
lobules quiescent
normal breast after ovulation
changes due to combined effect of E and P
- # of acini per lobule increases
- vacuolization of epithelial cells
- marked intralobular stromal edema
what happens to the normal breast during pregnancy
becomes completely mature and functional
lobules increase both in number and size
true secretory glands form in the lobule
secretory vacuoles of lipid material appear
what influences the changes that occur in the breast during pregnancy
E. P, prolactin, and placental lactogen
process of milk production
rising levels of E throughout pregnancy increase prolactin secretion
prolactin stimulates milk production
milk production is inhibited by high levels of P during pregnancy
lactation process
occurs after birth
- removal of the P inhibition on prolactin effect
- suckling > release of oxytocin > milk ejection by contraction of myoepithelial cells
colostrum
immediately after delivery
high in protein
what changes occur in milk
becomes higher in fat and calories within the first 10 days
where are prolactin receptors
on inner epithelial cells
where are oxytocin receptors
on outer myoepithelial cells
secretory products from mammary alveolar cells
fat
dimeric IgA
protein
lactose
dimeric IgA in breast milk
produced by plasma cells, transported into the lumen by transcytosis and released into the milk to provide passive immunity to the nursing baby
what does breast milk provide to an infant
complete nourishment
protection against infection and allergies
what happens in the normal breast after cessation of lactation
lobules regress and atrophy
postmenopausal breast changes
atrophy of ducts and lobules
shrinkage of intralobular and interlobular stroma
radio-dense fibrous interlobular stroma is progressively replaced by radiolucent adipose tissue
lobular acini and stroma may almost totally disappear
presentations of breast disease
pain
palpable masses
lumpiness
nipple discharge
source of pain in breasts
ruptured cysts
prior injury
infection
no lesion
nipple discharge
bloody or serous are most commonly associated with benign lesions
most common etiology is intraductal papilloma
milky nipple discharge not associated with malignancy
most worrisome when spontaneous and unilateral
sens and spec of mammography
increased with age as intralobular stroma is less dense
