Breast Histology

Question 1

Each breast lobe consists of a compound tubulo-acinar gland. Approx. how many lobes are there per breast?

Answer 1

15-25 lobes

Question 2

What interlobular tissues surround the secretory lobules of the breast?

Answer 2

dense fibrocollagenous connective tissue which is then surrounded by adipose tissue between lobes

Question 3

What are the suspensory ligaments & what do they connect?

Answer 3

fibrous connective tissue bands that extend from the dermis of the skin to the deep fascia over the anterior chest wall muscles

Question 4

What is the basic functional secretory unit of the breast?

Answer 4

Terminal Duct Lobular Unit (TDLU)

Question 5

In non-lactating breast, terminal ductules lead where?

Answer 5

into interlobular collecting duct which leads into the lactiferous duct for that lobe which leads to the nipple

Question 6

What is the lactiferous sinus?

Answer 6

an expanded part of the lactiferous duct near the nipple that acts as resevoir for milk, duct narrows again to exit areola

Question 7

Which is the fibrocollagenous tissue looser around the acini AKA terminal ductules?

Answer 7

to allow rapid expansion in pregnancy

Question 8

Contractile epithelial cells surround the secretory cells of the acinus, what are they called?

Answer 8

myoepithelial cells (MEp)

Question 9

What type of secretory epithelial cells that line the acini?

Answer 9

cuboidal and columnar cells

Question 10

What type of epithelial cells line the lactiferous duct?

Answer 10

varies, further to nipple is stratified squamous and deeper is stratified cuboidal , may be only 1 cell thick in deep part

Question 11

How do MEp cells appear on histology sections?

Answer 11

pink lines around the cells

Question 12

What cells line the outer nipple surface?

Answer 12

thin, highly pigmented keratinised stratified squamous epithelium

Question 13

What tissue makes up the core of nipples that the lactiferous ducts pass through?

Answer 13

fibrocollagenous tissue mixed with smooth muscle bundles

Question 14

What glands are found in the skin surface of nipple?

Answer 14

sebaceous glands

Question 15

What 3 changes occur to mammary gland during the luteal phase of menstrual cycle?

Answer 15

epithelial cells increase in height,
lamina of ducts enlarge,
small amounts of secretions appear in ducts

Question 16

What 2 changes occur to the mammary glands in first trimester of pregnancy?

Answer 16

elongation & branching of small ducts,

proliferation of epithelial and myoepithelial cells of glands

Question 17

What 2 changes occur to the mammary glands in second trimester of pregnancy?

Answer 17

glandular tissue develops with differentiation of secretory alveoli,
plasma cells and lymphocytes infiltrate the connective tissue around glands

Question 18

What change occurs to the mammary glands in third trimester of pregnancy?

Answer 18

secretory alveoli mature with development of extensive rER

Question 19

What change occurs to breasts during all three trimesters of pregnancy?

Answer 19

Reduction of connective and adipose tissue

Question 20

What hormones stimulate proliferation of secretory tissue and reduction in fibro-fatty tissue in pregnancy?

Answer 20

Oestrogen and progesterone

Question 21

Compositions of human milks are approx. 
88% ?
7% ?
3.5% ?
1.5% ? 
small quantities of ?,? and ?

Answer 21

88% water,
7% carbohydrate, 
3.5% lipid, 
1.5% protein, 
small quantities of ions, vitamins and IgA

Question 22

How are lipid droplets secreted from terminal ductules?

Answer 22

Apocrine secretion = surrounded by membrane with small amount of cytoplasm

Question 23

How are proteins secreted from terminal ductules?

Answer 23

Merocrine secretion = via vesicles which merge with apical membrane to release contents into ducts system

Question 24

Where are proteins for breast milk are made & packaged?

Answer 24

made in rER and packaged in Golgi apparatus

Question 25

What 2 changes occur to breast tissue post-menopause?

Answer 25

secretory cells of TDLU’s degenerate so only ducts left,

boobs sag cos less connective tissue due to reduced fibroblasts, collagen and elastic fibres

Question 26

Blood supply of breast?

Answer 26

lateral mammary branches from lateral thoracic artery from axillary,
medial mammary branches from internal thoracic from subclavian artery

Question 27

Venous drainage of breast?

Answer 27

lateral from lateral mammary veins drains into axillary vein,
medial from medial mammary vein which drains into ipsilateral brachiocephalic veins

Question 28

Lymph drainage of breasts?

Answer 28

> 75% to ipsilateral axillary lymph nodes

rest to parasternal nodes and maybe to abdomen nodes

Question 29

What is the name of the lymph collection structure around the nipple?

Answer 29

sub areolar lymphatic plexus