THE BREAST Flashcards
what hormones does the growth and differentiation of the mammary depend on?
LH, oestrogen , proges`terone, human placental lactogen, prolactin, adrenocorticotropic hormone, human growth hormone
what produces oestrogen and progesterone during pregnancy?
ovaries and then the placenta takes over from the 10th week as the corpus luteum degenerates
what’s the role of oestrogen in mammary growth?
stimulating milk ductal growth and proliferation
what’s the role of progesterone on mammary growth?
stimulates production of milk glands
where is human placental lactogen secreted from?
the placenta
note: its also known as human chorionic somatomammotropin
whats the role of human placental lactogen in mammary development?
stimulates ductal and aereolar growth
where is prolactin secreted from?
lactotrophs in anterior pituitary
whats the role of prolactin in mammary development?
promotes the growth of the alveoli
where is adrenocorticotropic hormone released from?
anterior pituitary
where is human growth hormone released from?
anterior pituitary
what is mammogenesis?
the process of growth and development of the mammary gland in preparation for milk production
when is mammogenesis fully complete?
after pregnancy and lactation - about 35
outline the embryological derivatives of the breasts?
the ectoderm is responsible for the formation of the ducts and alveoli and the mesenchyme is responsible for the connective tissue and its vessels.
what happens at 4 gestational weeks in mamogenesis?
two milk lines form from axilla to groin caused by a thickening of epithelia cells
what happens at 7/8 gestational weeks in mammogenesis?
thickening and inward growth of epithelia cells causes milk hillocks
what happens at 12-16 gestational weeks in mammogenesis?
epithelial cells form mammary buds which branch to form a network of alveoli
what happens at 28-32 gestational weeks in mammogenesis?
canalization of branch epihtleial tissue. Primary milk ducts are formed
what happens at 32-40 gestational weeks in mamogenesis?
lobular-alveolar structures containing colostrum develop
ducts open onto the area which becomes the nipple
nipple and areola develop and become pigmented
Outlien the difference in growth pattern of te breast through childhood and puberty?
in childhood there is isometric growth of the breast
in pubert we get allometric growth of the breast caused by oestrogen and progesterone
what happens to the breasts in puberty?
budding and branching of glandular tissues to form small ductules and then alveoli. Fat deposition creates the shape and size of the breast
what happens to our breatss in every reproductive cycle?
proliferation and active growth of mammary glands - this is why we get breast tenderness
what is the areolar?
a circular area of pigmented skin that includes openings for about 20 sebaceous glands and is attached to a lactiferous lobule
whats the structure of the nipple?
surrounded by the areolar
it has 10-20 nipple openings connected to lactiferoud ducts which allow milk out
what are the tubercules of montgomery?
sebaceous glands that appear as small bumps around the areolar. they are important for lubrication, keeping germs away from breasts and for secreting pheremones
what is the Axillary tail of Spence?
A tail of breast tissue extending towards the axilla
where would a supernumery nipple appear?
somewhere along the embryonic milk line
how does the different sizes in breast affect milk production?
women produce milk based on the amount of glandular tissue not adipose tissue so size doesnt affect it, however, small breasts do have less storage capacity so may have to feed more often
outline the structure of the secretory unit of the breast?
each breast lobule consists of clusters of hollow alveoli lined by a single layer of lactocytes (milk secreting epithelial cells). These are continuous with the lactiferous duct which is lined by myoepithelial cells
there is a efficient blood supply here too
whats the blood supply to the breast?
60% from internal thoracic artery and 30% from lateral thoracic artery