Repro Session 11 Flashcards
why does breast enlarge at puberty in female?
under influence of oestrogens AT accumulates, and lactiferous ducts become much enlarged
what cells surround the lactiferous ducts in the breast?
myoepithelial cells
why can oedema and tenderness occur in the breasts within the week prior to the menses?
oestrogen peak stimulates mammary glands further in the menstrual cycle as it induces duct proliferation which causes ducts to enlarge and may cause oedema and tenderness
action of progesterone on breast in pregnancy?
influences development of secretory tissues
action of oestrogen on breast in pregnancy?
duct proliferation
where does base of mature breast extend?
from lateral border of sternum to mid-axillary line, and overlies 2nd to 6th ribs
major features of female breast?
nipple
areola
axillary tail
what does each lactiferous duct of each lobule of the breast comprise just prior to its opening onto the nipple?
a dilated lactiferous sinus
how is each lobule of glandular tissue in the breast delineated?
by CT septa extending from skin into deep fascia, known as suspensory ligaments
what does skin of areola comprise?
many tubercles produced by underlying alveolar glands
why is the breast mobile?
due to retromammary space between breast and fascia overlying the chest wall muscles
what changes to the breast may be visualised if a tumour is present?
distortion due to shortening of suspensory ligaments, and dimpling of skin due to oedema
blood supply to breast?
internal thoracic artery
intercostal artery
lateral thoracic
thoracoacromial
venous drainage of breast?
axillary vein
posterior IC veins
internal thoracic vein
lymphatic drainage of medial quadrants of breast?
parasternal nodes or opposite breast
most of lateral to axillary LNs
composition of lobes of breast?
lobules of alveoli- site of milk synthesis, and surrounded by myoepithelial cells
blood vessels
lactiferous ducts
what is secreted from the breast during the 1st week after birth?
colostrum: contains less H20 soluble vits, fat and sugar than later milk but more protein, fat-soluble vits and Igs
IgG and total protein declines over next 2-3wks, whilst fat and sugar rises to produce mature milk
where is milk fat synthesised?
smooth ER of alveolar cells and passes in membrane bound droplets towards lumen
where does milk protein pass through?
golgi apparatus and is released by exocytosis
what favours development of alveoli during preganancy?
a higher progesterone to oestrogen ratio
how do alveolar cells become responsive to prolactin at birth?
fall in progesterone levels, with fall in oestrogen less so
how does suckling maintain milk secretion?
neuro-endocrine reflex: suckling by infant stimulates receptors in nipple mechanically which results in impulses being sent up to brain stem and hypothalamus to reduce dopamine secretion and VIP so promoting prolactin secretion
what is milk ‘let down’
dramatic increase in oxytocin secretion when infant next suckles, which contracts myoepithelial cells which eject the milk
what doe maintenance of lactation depend on?
regular suckling to promote prolactin secretion, and tp remove accumulated milk
what can a mother take to suppress milk production?
steroids= -ve feedback on anter.pituitary to inhibit prolactin release?
why will milk production cease if suckling stops?
decrease in prolactin and damage to breast due to turgor-induced damage
why is a new pregnancy unlikely during the time in which an infant is suckling?
fertility is reduced due to high prolactin
physiological breast changes in menarche?
increase in no. of lobules and increase in volume of interlobular stroma
physiological breast changes in menstrual cycle?
follicular phase: lobules quiescent
after ovulation: cell proliferation and stromal oedema
menses: decrease in size of lobules
physiological breast changes in pregnancy?
increase in size (hypertrophy) and number of lobules
decrease in stroma
secretory changes
clinical presentation of breast conditions?
Pain Palpable mass Nipple discharge Skin changes Lumpiness
cause of cyclical and diffuse pain in breast?
physiological e.g. in menstrual cycle
cause of non-cyclical and focal pain in breast?
ruptured cysts, injury, inflammation
triple approach to diagnosis and investigation of breast cancer?
clinical- history, FH, examination
radiographic imaging- mammogram and USS
pathology- fine needle aspiration and cytology and core biopsy
characteristics of an in situ breast carcinoma?
Neoplastic population of cells limited to ducts and lobules by BM, myoepithelial cells are preserved
Does not invade into vessels so can’t metastasise
how does a ductal carcinoma in situ most commonly present?
mammographic calcifications- clusters or linear and branching, but can present as a mass
histological appearance of a ductal carcinoma in situ?
central necrosis with calcification
how does invasive breast carcinoma commonly present?
mass or mammographic abnormality
over 50% will have metastasised to axillary LNs by time lump is found
why is breast turgor increased between feeds?
milk accumulates in alveoli and ducts as suckling at 1 feed promotes prolactin release which causes production of next feed
define physiological breast changes
changes or symptoms that come about due to normal breast physiology
physiological breast changes in menarche?
increase in lobule number, increase vol of interlobular stroma