Histology of the breast

Question 1

What is the secretory tissue of the breast made up of?

Answer 1

15-25 lobes

Question 2

What makes up a lobe?

Answer 2

tubulo-acinar glands

Question 3

What are suspensory ligaments?

Answer 3

larger condensations that extend from the dermis of the skin to the deep fascia overlying the muscle of the anterior chest wall

Question 4

What is the role of suspensory ligaments?

Answer 4

support breast tissue

Question 5

What is the Terminal Duct Lobule Unit (TDLU)?

Answer 5

basic functional secretory unit of the breast

Question 6

What is the passage between the terminal ductules and the lactiferous duct?

Answer 6

terminal ductules -> interlobular collecting duct -> lactiferous duct -> nipple

Question 7

What lines acinis?

Answer 7

secretory epithelial cells - cuboidal or columnar

these are surrounded by myoepithelial cells

Question 8

What are myoepithelial cells?

Answer 8

contractile epithelial cells that are surrounded by the basal lamina

Question 9

What lines larger ducts?

Answer 9

either stratified squamous or stratified columnar epithelium

Question 10

What covers the nipple?

Answer 10

highly pigmented keratinised stratified squamous epithelium

Question 11

What is the core of the nipple made of?

Answer 11

dense irreguar connective tissue mixed with smooth muscle

Question 12

How does the nipple change during the luteal phase of the menstrual cycle?

Answer 12

epithelial cells increase in height
lamina of ducts become enlarged
small amounts of secretions appear in ducts

Question 13

How does the nipple change during the first trimester of pregnancy?

Answer 13

elongation and branching of the smaller ducts

proliferation of epithelial and myoepithelial cells

Question 14

How does the nipple change during the second trimester of pregnancy?

Answer 14

glandular tissue develops and differentiates into secretory alveoli
plasma cells and lymphocytes infiltrate nearby connective tissue

Question 15

How does the nipple change during the third trimester of pregnancy?

Answer 15

secretory alveoli continue to mature with the development of extensive rER

Question 16

What part of the breast does oestrogen grow?

Answer 16

lobules

Question 17

What part of the breast does progesterone grow?

Answer 17

ducts

Question 18

What is the composition of human milk?

Answer 18

88% water
1.5% protein
7% carbohydrate
3.5% lipid

Question 19

What is apocrine secretion?

Answer 19

lipid droplets that are secreted by the membrane and carry a small amount of cytoplasm with it

Question 20

What is merocrine/eccrine secretion?

Answer 20

proteins in milk are made in the rER, packaged in the Golgi apparatus and secreted via vesicles which merge with the apical membrane to release their contents into the duct system

Question 21

How does the nipple change post menopause?

Answer 21

secretory cells in the TDLU degenerate, leaving only ducts