Breast Histology and Anatomy

Question 1

what makes up the secretory tissue of the breast

Answer 1

lobes- divided into lobules by dense connective tissue

15-25 lobules - each has a tubulo-acinae gland which drains via a series of ducts to the nipple

Question 2

what surrounds the secretory tissues of the breast

Answer 2

dense connective tissue

this is surrounded by adipose tissue

Question 3

what is the lactiferous sinus

Answer 3

expansion of the lactiferous duct before it reaches the nipple

Question 4

what are the suspensory ligaments of the breast

Answer 4

connective tissue that extends from dermis of skin to deep fascia overlying the muscle of ant chest wall
support the breast tissue

Question 5

what is the basic functional secretory unit of the breast

Answer 5

the terminal duct lobular unit

Question 6

what does the terminal ductules lead to in a non lactating breast

Answer 6

intralobular collecting duct which leads into the lacteiferous duct for that lobe

Question 7

what does the lacteriferous duct lead to

Answer 7

the nipple

Question 8

what proliferates in a lactating breast

Answer 8

terminal duct lobular unit

Question 9

what structures are associated with lobule

Answer 9

Both extralobular and intralobular ducts

Rudimentary secretory acini

Dense fibrocollagenous connective tissue surrounding the lobule

Looser connective tissue surrounding the acini within the lobule (this allows rapid expansion in pregnancy)

Adipose tissue between lobules

Question 10

what cells line the acini

Answer 10

secretory epithelial cells

vary from cuboidal to columnar

Question 11

what are the myoepithelial cells of the breast

Answer 11

surround the secretory cells that line the acini

are contractile epithelial cells (are surrounded by basil lamina) that work to push material our o the duct system

Question 12

what is an acnini

Answer 12

termonal ductal lobular unit

Question 13

what does loos connective tissue in the mammary gland allow

Answer 13

proliferation

Question 14

what lines lactiferous ducts

Answer 14

epithelium that varies from thin stratified squamous (as reaches surface of nipple) to stratified cuboidal (deeper)

Question 15

what is the histology of the nipple

Answer 15

surface is highly pigmented, keratinized squamous epithelium
core is dense irregular connective tissue mixed with smooth muscle bundles
will contain several latiferous ducts
sebaceous glands open directly onto skin as have no hair (holocrine excretion- cell explodes)

Question 16

what happens to the breast during menstruation

Answer 16

in luteal phase epithelual cells increase in height- enlarging lumina of the ducts
small amounts of secretions appear in the ducts

Question 17

what happens to the breast in pregnancy

Answer 17

1st trim- elongation and branching of smaller ducts, proliferation of epithelial cells of glands and of myoepithelium
2nd trim- glandular tissue continues to develop: differentiation of secretory alveoli, plasma cell and lymphocyte infiltrate nearby connective tissue
3rd trim- secretory alvioli mature, development of extensive rough endoplasmic reticulum

also reduction in connective and adipose tissue

Question 18

what are alveoli

Answer 18

acini

Question 19

what are the effects of oestrogen and progesterone on the breast

Answer 19

stimulate proliferation of secretory tissue and fibro fatty tissue becomes sparse

Question 20

what is the composition of human milk

Answer 20

88% water
1.5% protein (lactalbumin and casein)
7% carbohydrate (mainly lactose)
3.5% lipid

small quantities of ions, vitamins and IgA antibodies

Question 21

how is the lipid component of breast milk secreted

Answer 21

apocrine secretion= Lipid droplets are secreted surrounded by membrane and carrying a small amount of cytoplasm with it

Question 22

how are the proteins in milk made

Answer 22

made in rER

packaged in golgi apparatus

Question 23

how are the proteins in milk secreted

Answer 23

merocrine secretion (exocytosis) secreted via vesicles which merge with the apical membrane to release only their contents into the duct system
only proteins are secretion, no membrane or cytoplasms alongside

Question 24

what happens to the breast following menopause

Answer 24

secretory cells of TDLU degenerate leaving only ducts

reduced fibroblasts, collagen and elastic fibres in connective tissue

Question 25

can males get breast cancer

Answer 25

yes have rudimentary element of duct system so have small amounts of epithelium

Question 26

what is breast cancer in situ

Answer 26

still within duct (ductal is a common form of breast cancer)