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25 Cards in this Set

  • Front
  • Back
What types of glands are mammary glands and what are they derived from?
-Specialized accessory glands.
-Are really Modified Apocrine Sweat Glands
-Are Ectodermally Derived
Development - Embryo: Mammary Ridges, Primary Bud, Secondary Buds, Lactiferous Ducts, Supernumary Nipples
-During the 4th week of development, a pair of epidermal thickenings called Mammary Ridges develop along either side of the body.
-At the site of breast development (and future nipple), the epidermis proliferates into the underlying dermis to form the Primary Bud
-By the 12th week, several Secondary Buds have formed, which become canalized to from the Lactiferous Ducts
-Sometimes portions of the mammary ridges persist (they normally disappear) and Supernumary Nipples result (Polythelia)
Development - Infantile
The breast consists of rudimentary (lactiferous) ducts surrounded by abundant CT
Development - Puberty: Ovarian Estrogens and 3 mechanisms, and mammary glands in males
-In females, breast develop under the influence of Ovarian Estrogens via 3 mechanisms
1) Accumulation of CT
2) Accumulation of adipose tissue
3) Proliferation of ducts deep in the breast to form lobules

-In males, since there is minimal estrogen present, the mammary glands retain the infantile structure
Breast consists of what types of glands and where do they reside, lobules and ducts, alveoli
-The breast consists of 15-20 Compound Tubuloalveolar Glands that reside in 15-20 Lobes.
-The lobes contain Lobules that contain clusters of Ducts, which in the Active breast, become Alveoli (secretory units).
Intralobular CT vs. Interlobular CT
The Intralobular CT is slightly less dense and is more cellular than the Interlobular CT, which contains adipose tissue
Secretory Alveoli - epithelium, cells found here
-Lined by a single layer of epithelial cells that may be cuboidal or columnar
-Myoepthelial Cells lie between the base of the epithelium and the basement membrane - important part of the milk ejection reflex
Intralobular ducts - reside where, function, epithelium, cells found, drain into what
-Reside Within the Lobules
-Drain the secretory alveoli
-Simple cuboidal - these cells also secrete so hard to find in EM
-Myoepithelial cells found beneath the epithelium
-The intralobular ducts of each lobule drain into the Interlobular Ducts (located in the CT BETWEEN lobules) that are lined with simple cuboidal and have myoepithelial cells present
Each lobe is drained by...
Epithelium of what drains it
-Drained by a Lactiferous Duct which receives contents of the interlobular ducts within the lobe
-Stratified cuboidal/columnnar
Each lactiferous duct becomes...
Epithelium of what it becomes
-Widens at the nipple to become the Lactiferous sinus
-Epithelium becomes stratified squamous at the opening of the nipple
Nipple - covered by what type of epithelium, CT around the lactiferous ducts is rich in what 2 things and what are they essential for
-Covered by keratinized stratified squamous (skin) that is continuous with the pigmented Areola and the surrounding skin.
-The CT around the ducts in the nipple is rich in smooth muscle and sensory nerve endings, which are essential for the Milk Ejection Reflex to occur during nursing
Functional Changes in the Adult Mammary Glands: Resting (inactive) Breast - milk secretions and lobules
-Is not secreting or preparing to secrete milk, so there are few secretory alveoli.
-Lobules contain small clusters of blind-ended ducts embedded in loose CT
Functional Changes in the Adult Mammary Glands: Active Breast - hormones (4) and their functions, and changes in epithelium
-If pregnancy occurs, the hormones Estrogen, Progesterone, Prolactin (from pituitary), and hCS are released.
-Estrogen and Progesterone act on breast tissue and cause intense proliferation of ducts and secretory alveoli. They inhibit the effects of prolactin and hCS prior to birth.
-After birth, the effects of hCS allow lactation to begin and the simple columnar epithelium of the alveoli becomes low cuboidal as milk production increases.
Active Breast - Lactation: components of milk (4) - protein secretion, lipid secretion
-Milk contains lipids, proteins, immunoglobins (secretory IgA) and sugars.
-Proteins are formed in the RER, packaged into vesicles by the Golgi and secreted by Exocytosis (Merocrine secretion) into the lumen of the alveolus.
-Lipid arises as free floating droplets in cytoplasm, fuse into larger ones are they project into the lumen. THey break free, enveloped by small amount of cytoplasm and a portion of the cell membrane, called an Apocrine Secretion
Active Breast - Colostrum - what is it, contains what and what do these components do
-Colostrum is a very low fat, high protein secretion that is produced right after birth.
-Contains Secretory IgA (immunoglobins) derived from plasma cells present in the CT
-These immunoglobins confer Passive Immunity to the suckling infant.
Active Breast - Prolactin and Prolactin Inhibitory Factor (PIF)
-After birth, the placental hormones are no longer secreted and the breast activity is maintained by prolactin.
-The pituitary gland is stimulated to secrete prolactin by the infant suckling
-The production of hypothalamic PIF is inhibited by suckling.
-PIF inhibits the production and release of prolactin
Active Breast - Milk Ejection Reflex, Oxytocin - released from where, what does it do
-Milk Ejection Reflex occurs when the tactile receptors in the nipple are stimulated by suckling.
-In this relfex, the hormone Oxytocin is released from the Neurohypophysis (neural lobe of pituitary gland) into the bloodstream
-Oxytocin rapidly stimulates contraction of myoepithelial cells surrounding secretory alveoli and ducts, resulting in release of milk from nipple
Functional Changes in Adult Mammary Glands - Regression of the Mammary Gland - when does it happen and what happens to alveoli
-Occurs when suckling by the infant ceases (weaning).
-During first few days, alveolar epithelium is flattened due to distension of alveoli w/milk, alveoli gradually collapse, increase in CT and adipose tissue.
-Number of intraepithelial macrophages increases, most of alveoli are replaced by the CT and remaining appear as scattered cords of epithelial cells
Functional Changes in Adult Mammary Glands - Involution of the Mammary Gland - occurs when, what happens to alveoli and ducts, and to the gland
-Occurs after menopause b/c of reduction in circulating estrogen
-Epithelium of alveoli and ducts atrophies, reduction in adipose tissue, and gland returns to a prepubertal condition (mostly CT w/few ducts)
Clinical Significance - Chronic Cystic Disease
-the intralobular discs may lose their continuity with the remainder of the duct system and fluid filled cysts of varying sizes are formed
Clinical Significance - Gynecomastia
-Most common Male Breast Disorder
-Not a tumor but rather just an increase in the amount of a man's breast tissue.
-Common among teenage boys due to changes in hormone balance during adolescence.
-Rarely, it can Gynecomastia can occur b/c tumors or diseases of certain endocrine glands cause a man's body to produce more estrogen
Clinical Significance - Carcinoma (3 types)
-The breast is the most common site of cancer in women and carcinomas can arise from the glandular and ductal structures of the breast; most arise from the lactiferous ducts
1) Ductal Carcinoma In Situ (DCIS)
2) Infiltrating (invasive) Ductal Carcinoma (IDC)
3) Infiltrating (invasive) Lobular Carcinoma (ILC)
-There are also several less common types of breast cancer. Men can develop breast cancer; the most common is IDC
Ductal Carcinoma In Situ (DCIS)
-This is breast cancer at its earliest stage (0).
-The cancer is confined to the ducts and has not spread through the walls of the ducts into the fatty tissue of the breast.
-Best way to find it is w/mammogram, its almost always curable
Infiltrating (invasive) Ductal Carcinoma (IDC)
-This cancer starts in a duct, breaks through the wall of the duct, and invades fatty tissue of the breast
-From there it can spread.
-IDC is the most common type of breast cancer - 80% of cases
Infiltrating (invasive) Lobular Carcinoma (ILC)
-This cancer starts in the milk glands (lobules) and then can spread
-Between 10-15% of invasive breast cancers are of this type.