Mammary Histology Flashcards
Technially, the mammary gland is what?
a modifed sweat gland
HOw many lobes are there?`
15-25
True or false: each lobe is an independent gland
true
Where do ducts open?
apex of the nippple
Each lobe has several what?
lobules separated by intralobular connective tissue
Which CT is thicker - the interlobular or intralobular?
interlobular
the intralobular is loose
What is the secretory unit of the mammary gland?
alveoli
What kind of secretion is this?
apocrine - the lipid part
merocrine - the salts and proteins
What is the epithelium of the duct system? How bout near the opening on the nipple?
simple columnar in the ducts
stratified squamous near the opening on the nipple
WHat cells help to squeeze the alveoli to push the milk into the duct system and out?
the myoepithelial cells
What is the sequence of ducts in the gland?
intralobular ducts interlobular ducts lactiferous ducts lactiferous sinus lactiferous duct
What are the changes that occur during puberty?
- glands enlarge rapidly due to distribution and deposition of adipose and CT
- the duct system may enlarge slightly, but stays relatively unchanged and remain incompletely developed until first pregnancy
WHen does the fullest development occur for the mammary gland?
during nursing for the first child
Describe the skin of the nipple?
- pigmented
- stratified squamous keratinized epithelium
- no sweat glands or hair follicles, but maybe solitary sebaceous glands
- melanin increases during pregnancy
- tall connective tissue papillae with numerous meissner’s corpuscles
Describe the smooth muscle arrangement in the hipple?
outer circumferential and inner longitudinal surrounding the ducts (hard to differentiate)
What are the little bumps on the areola called?
areolar glands of Montgomery
What are these glands of montgomery?
intermediate between sweat glands and a true mammary gland
True or false: aerola has no sweat glands, but has sebaceous glands.
false - has both
Where are the alveoli located?
at the distal ends of the intralobular ducts
What is the epithelium of those alveoli?
cuboidal to squamous epithelium
How many myoepithelial cells are there per alveolus?
usually 4-6
What hormone do those myoepithelial cells respond to?
oxytocin
What’s the term for one set of duct lobules?
terminal duct lobular unit
What happens to the breast during pregnancy?
- intralobualr ducts proliferate and branch
- alveoli form and increase in numbers
- CT appears to decrease, but is actually just compressed
- plasma cell infiltration
- increase in alveolar height
- clostrium pruduction
When during pregnancy do the alveoli develop lumens?
2nd half
Describe colostrum
It’s a type of pre-milk that is thick with proteins, vitamin A, sodium, chloride, lactalbumin and IgA
WHat is the major milk sugar produced by the active alveoli?
lactose
Adjacent to the active alveoli will be resting alveoli (which already ejected its milk). What would those look like in comparison?
- small lumen
2. epithelium may be taller because it’s preparing to make more milk
Describe how foremilk at the beginning of nursing differs from hindmilk of later nursing session?
foremilk - more watery, lots o protein
hindmilk - thicker, more lipid
Describe what happens in regression after breastfeedign?
- secretory products resorbed
- aleolar size decreases
- alveolar degeneration
- connective tissue appears to increase as the alveoli degenerate
What happems to the mammary glands during menopause?
involution
Describe what happens in involution?
- atrophy of gland and stroma
- few ducts may persist
- cyst formagion is common
- the CT becomes more dense
WHat hormone will stimulate the duct proliferation during pregnancy?
estrogen
What hormone stimulates alveolar proliferation?
progesteron
What hormone stimulates milk formation?
prolactin
What are the two effects of suckling?
- increases prolactin secretion (by decreasing dopamine release)
- increases oxytocin release to produce milk ejection via myoepithelial cell contraction
