Histology of the breast Flashcards
Where is the breast found?
Subcutaneously
What makes up the secretory tissue of the breast?
15-25 lobules
Each consist of a compound tubulo-acinar gland which drains via a series of ducts leading to the nipple
What is found adjacent to the secretory lobules?
Dense fibrous tissue
Adipose tissue
What are the suspensory ligaments of the breast?
Larger areas of connective tissue that extend from dermis of skin to the deep fascia overlying the muscle of the anterior chest wall
What is the function of the suspensory ligaments of the breast?
Support breast tissue
Found predominantly in the upper breast tissue
What is the basic functional secretory unit of the breast?
Terminal Duct Lobular Unit (TDLU)
Where will terminal ductules lead to in a non-lactating breast?
Intralobular collecting duct which leads into the lactiferous duct for that lobe
What does the lactiferous duct turn into when it reaches the nipple?
Lactiferous sinus
What does the lobule of the breast exhibit?
Extralobular and intralobular ducts
Rudimentary secretory acini
Dense fibrocollagenous connective tissue surrounding lobule
Looser connective tissue surrounding acini within lobule
Adipose tissue between lobules
What type of epithelium lines the acini?
Secretory epithelial cells; vary from cuboidal to columnar
What surrounds the secretory cells of the acinus in the breast?
Myoepithelial cells (MEp) Contractile cells which are surrounded by basal lamina
What type of epithelium lines the lactiferous ducts?
Epithelium that varies from thin stratified squamous to stratified cuboidal
What type of epithelium covers the nipple
Highly pigmented keratinized stratified squamous epithelium
What makes up the core of f the nipple?
Dense irregular connective tissue mixed with bundles of smooth muscle
What is interesting about the sebaceous glands of the nipple?
Open directly onto the surface of the nipple
How does the breast change in the menstrual cycle?
Luteal phase; epithelial cells increase in height, lumina of duct is enlarged and small amounts of secretions appear in duct
How does the breast tissue change in the 1st trim?
Elongation and branching of epithelial cells of glands and myoepithelial cells
How does the breast tissue change in 2nd trim?
Glandular tissue continues to develop with differentiation of secretory alveoli Plasma cells (IgA) and lymphocytes infiltrate local connective tissue
How does the breast tissue change in the 3rd trim?
Secretory alveoli continue to mature with development of extensive RER
What is the action of oestrogen and progesterone in the lactating mammary gland?
Stimulate proliferation of secretory tissue and fibro-fatty tissue becomes sparse
What is the composition of human milk?
88% water 1.5% protein (lactalbumin and casein) 7% carbohydrate (lactose) 3.5% lipid Ions Vitamins IgA Ab
How are fat droplets secreted by the breast?
Secreted surrounded by membrane carrying a small amount of cytoplasm with it
APOCRINE secretion
How are the proteins in breast milk secreted by the breast?
Protein made in RER and packaged in golgi apparatus
Secreted via vesicles which merge with apical membrane to release contents into ductal system
MEROCRINE secretion
What happens to breast tissue post menopause?
Secretory cells of TDLUs degenerate leaving only ducts
In connective tissue, fewer fibroblasts and reduced collagen and elastic fibres
