Histology of the breast

Question 1

Basic structure of non lactating breast?

• breast position?
• secretory tissue?
• other tissue within the breast?
• name of ducts in breast?
• name the ligaments in the breast?

Answer 1

• subcutaneous structure, sits anterior to pectorales fascia
• made up of 15-25 lobes, each lobe consist of compound tubulo-acinar glands which drains via a series of ducts leading to the nipple

-dense fibrous tissue (adjacent to secretary lobules)
this is surrounded by adipose tissue)

• lactiferous ducts
• suspensory ligaments of cooper

Question 2

histological appearance of a non lactating breast?

Answer 2

large amount of amorphous looking pink material- this is adipose tissue
can see clusters of epithelial cells embedded in thicker more dense extracellular matrix
also see lactiferous ducts

Question 3

Describe the duct system within the breast

Answer 3

terminal ductules lead into an interlobular collecting duct that leads into the collecting duct for that lobe. this then leads to the nipple, passing through the lactiferous sinus and then exiting.

Question 4

what is the function of myoepithelial cells?

Answer 4

they are epithelial cells that have become contractile, they coat the duct system and contract to help fluid move along the ducts.

Question 5

what type of epithelium are lactiferous ducts lined by?

Answer 5

near surface- stratifies squamous epithelium, deeper- stratified cuboidal epithelium
secretory acini- cuboidal or low columnar

Question 6

describe a transverse section of the nipple:

• type of epithelium?
• core?
• ducts?

Answer 6

• highly pigmented keratinised stratified squamous epithelium
• dense irregular connective tissue (fibrocollagenous) mixed with bundles of smooth muscle

-also lactiferous sinuses
there are also sebaceous glands to secrete sebum and aid the chafing that suckling causes

Question 7

Holocrine secretion?

Answer 7

secretions are produced in the cytoplasm of the cell and released by the rupture of the plasma membrane, which destroys the cell and results in the secretion of the product into the lumen

Question 8

Apocrine secretion?

Answer 8

relating to or denoting multicellular glands which release some of their cytoplasm in their secretions, especially the sweat glands associated with hair follicles in the armpits and pubic regions.

Question 9

breast changes

• changes during the luteal phase?
• 1st trimester of Pregnancy?
• 2nd trimester pregnancy?
• 3rd trimester pregnancy?
• menopause?

Answer 9

-epithelial cells increase in height
lumina of the ducts becomes enlarged
small amounts of secretions appear in the ducts

-elongation & branching of the smaller ducts
proliferation of gland epithelial cells and myoepithelial cells

-glandular tissue development (differentiation of the secretory alveoli)
plasma cells & lymphocytes infiltrate the nearby connective tissue

-alveoli mature (development of extensive rER)

+reduction in the amount of connective and adipose tissue present

-secretory cells degenerate leaving ducts, fewer fibroblasts/collagen/elastic fibres in connective tissue

Question 10

composition of human milk?

Answer 10

88% water
1.5% protein (lactalbumin & casein)
7% carb (lactose)
3.5% lipid
\+ions, vit, Ig antibodies

Question 11

how are lipids in milk secreted?

Answer 11

apocrine secretion

Question 12

how are proteins in milk secreted?

Answer 12

merocrine secretion (vesicle)