Downing: Mammary Gland Histology Flashcards
specialized cutaneous gland/ modified sweat gland w/ 15-25 lobules that are each an INDEPENDENT gland
mammary gland
duct opens at APEX of nipple
lobules of mammary gland
several in each lobe
CT in lobule is loose, delicate, cellular
pathway of mammary gland ducts
intRAlobular ducts>
intERlobular ducts>
lactiferous duct>
lactiferous sinus
dilation of lactiferous duct just before it opens onto summit of nipple
lactiferous sinus
epithelium in smaller ducts
simple cuboidal
epithelium near opening of nipple
stratified sq
affect of puberty on mammary glands
ENLARGE d/t development of adipose and CT
when do mammary glands fully develop
pregnancy> finish developing w/ nursing
pigmented skin w/ no sweat glands or hair follicles
nipple
nipple epithelium
Strat, sq, keratinizing
melanin content in nipple during pregnancy
increases
contain numberous meissner’s corpuscles
Tall CT papillae of nipple
arranged LONGITUIDINALLY along lactiferous ducts
CIRCUMFERENTIALLY w/in nipple
smooth muscle
*permits erection of nipple in response to stimuli
area of skin surrounding nipple
areola
Glands in areola
areolar glands (between sweat gland and true mammary gland)
sweat gland
sebaceous gland
secretory units of mammary gland
alveoli
located at the distal ends of INTRAlobular ducts and have cuboidal to sq epithelium
alveoli
alveoli: merocrine secretion
secretory vesicle
alveoli: apocrine secretion
fat droplets
4-6 of these cells are found/alveolus and they encompass the epithelium
stellate
myoepithelial cells
alveoli w/ flattened cuboidal epithelium
FEW secretory vesicles
SMALL fat droplets
extensive CT and adipose
INACTIVE gland
what happens w/in the first trimester to mammary glands
intralobular ducts proliferate and BRANCH
increase in alveolar NUMBER
DECREASE in CT
infiltration of plasma cells
*lumens NOT distinct in first half of preg
what happens to the alveolar epithelum during the LAST HALF of pregnancy and what becomes prominent
increases!
lumen becomes prominent
rich in protein, low in lipid content
contains IgA
clostrum
When does clostrum production occur?
last half of pregnancy
active alevoli
dilated lumen cuboidal epithelium (smaller)
secretes milk!
rich in lactose, protein, lipids
milk!!
resting alveoli
small lumen
taller epithelium
contract and allow for milk ejection into ducts
myoepithelial cells
what happens during regression?
absorption of secretory products
decrease in size of alveoli
increase in CT adipose
postmenopausal phenomena that leads to atrophpy of gland parenchyma and stroma and the remainder of FEW ducts
CT becomes DENSE
Involution
what stage of life is cyst formation in the breast frequent?
postmenopausal involution
stimulates duct proliferation
estradiol
stimulates ALVEOLAR proliferation
progesterone
furthers gland development in last HALF of pregnancy
prolactin
stimulates casein production and lactose synthetase
prolactin
what permits prolactin levels to be enhanced
dropping levels of progesteron and estrogen AFTER BIRTH
increases PRL secretion by decreasing PIF
suckling reflex
oxytocin release>
leads to myoepithelial contraction and accumulation of milk in lactiferous sinuses
milk ejection reflex
