Histology of the Breast

Question 1

how many lobules does the breast consist of?

Answer 1

15-25

Question 2

what do the lobules in the breast consist of?

Answer 2

tubule-acinar gland which drains via a series of ducts to the nipple

Question 3

what surrounds the lobules of the breast?

Answer 3

dense fibrous tissue and adipose tissue

plus suspensory ligaments

Question 4

what are suspensory ligaments made of?

Answer 4

largest condensations of connective tissue

Question 5

where do the suspensory ligaments attach?

Answer 5

dermis to muscles of anterior chest wall

Question 6

what is the terminal duct lobular unit (TDLU)?

Answer 6

basic functional secretory unit of the breast

Question 7

describe the duct drainage pathway in the breast

Answer 7

terminal ductules > intralobular collecting duct > lactiferous duct > lactiferous sinus > nipple

Question 8

structures in the lobule

Answer 8

extralobular and intralobular ducts
secretory acini
fibro-collagenous connective tissue
adipose tissue

Question 9

what lines the acini?

Answer 9

cuboidal and columnar epithelium

surrounded by myoepithelial cells

Question 10

what are myoepithelial cells?

Answer 10

contractile cells surrounded by basal lamina

Question 11

lining of lactiferous ducts?

Answer 11

stratified squamous at their surface and stratified cuboidal cells deeper

Question 12

structure of the nipple?

Answer 12

wrinkled surface with highly pigmented, keratinised, stratified squamous epithelium

Question 13

luteal phase changes to the breast

Answer 13

epithelial cells increase in height, lumina become enlarged and small amounts of secretions occur

Question 14

1st trimester breast changes in pregnancy

Answer 14

elongation and branching of smaller ducts with proliferation of epithelial and myoepithelial cells

Question 15

2nd trimester breast changes

Answer 15

glandular tissue develops
plasma IgA
lymphocyte infiltrate

Question 16

3rd trimester breast changes

Answer 16

secretory alveoli mature with development of RER (protein synthesis)

Question 17

breast changes in menopause

Answer 17

secretory cells degenerate

fewer fibroblasts, collagen and elastic fibres

Question 18

components of human milk

Answer 18

88% water
7% carbohydrate (lactose)
3.5% lipid
1.5% protein (lactalbumin and casein)
ions
vitamins
IgA

Question 19

apocrine secretion

Answer 19

lipid droplets are secreted surrounded by a membrane carrying a small amount of cytoplasm with it

Question 20

merocrine secretion

Answer 20

proteins made in RER, packaged in golgi are secreted which merge with apical membrane to release only their contents into the duct system (exocyotosis)

Question 21

arterial supply to the breast

Answer 21

lateral mammary from lateral thoracic
medial mammary from internal thoracic

from subclavian

Question 22

venous drainage of the breast

Answer 22

medial and lateral mammary veins