Anatomy and Histology of the Breast

Question 1

What kind of gland is the breast?

Answer 1

Subcutaneous gland

Question 2

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

Answer 2

15-25 lobes = each consist of a compound tubulo-acinar gland

Question 3

What drains the tubulo-acinar gland of the breast lobes?

Answer 3

Drains via a series of ducts leading to the nipple

Question 4

What is adjacent to the secretory lobes of the breast?

Answer 4

Dense fibrous tissue = this is in turn surrounded by adipose tissue

Question 5

What are the suspensory ligaments?

Answer 5

Larger condensations among fibrous connective tissue

Question 6

Where do the suspensory ligaments extend?

Answer 6

From dermis to deep fascia overlying muscle of anterior chest wall

Question 7

Where are the suspensory ligaments most pronounced?

Answer 7

In the upper breast = thought to support breast tissue

Question 8

What is the basic functional secretory unit of the breast?

Answer 8

Terminal duct lobular unit

Question 9

How is the duct system organised in the non-lactating breast?

Answer 9

Terminal ductules lead into an intralobular collecting duct which leads into lactiferous duct for that lobe

Question 10

Where does the lactiferous duct lead?

Answer 10

To the nipple = passes through an expanded duct region near the nipple called the lactiferous sinus

Question 11

What kind of ducts exist in the lobule of the breast?

Answer 11

Both intralobular and extralobular ducts

Question 12

What surrounds the lobule of the breast?

Answer 12

Dense fibrocollagenous tissue

Question 13

What are some features of the lobule?

Answer 13

Adipose tissue between lobules

Rudimentary secretory acini

Question 14

What surrounds the acini in each lobule?

Answer 14

Looser connective tissue = allows rapid expansion during pregnancy

Question 15

What cell type line the acini of the lobule?

Answer 15

Secretory epithelial cells = vary from cuboidal to columnar

Question 16

What surrounds the secretory cells of the acini?

Answer 16

Myoepithelial cells = contractile epithelial cells which are in turn surrounded by basal lamina

Question 17

What lines larger ducts?

Answer 17

Epithelium = varies from thin stratified squamous to stratified cuboidal

Question 18

What does red staining of the duct represent?

Answer 18

Usually represents coagulated proteinaceous material

Question 19

What is the surface of the nipple like?

Answer 19

Wrinkled surface and is covered by a thin highly pigmented keratinised stratified squamous epithelium

Question 20

What does the core of the nipple consist of?

Answer 20

Dense irregular connective tissue mixed with bundles of smooth muscle

Question 21

How many lobes of the breast does each lactiferous duct serve?

Answer 21

One duct serves each lobe

Question 22

What cell types line the lactiferous duct?

Answer 22

Near surface = stratified epithelium

Deeper from skin = stratified cuboidal epithelium

Question 23

How thick can lactiferous ducts be deeper beneath the skin?

Answer 23

May only be one cell thick

Question 24

What glands are present in the nipple?

Answer 24

Sebaceous glands = end directly on the surface of the skin

Question 25

What changes occur in mammary glands during the luteal phase of the menstrual cycle?

Answer 25

Epithelial cells increase in height Lumina of the duct enlarges Small amounts of secretions appear in ducts

Question 26

Can changes occur in the mammary gland during the menstrual cycle even in the absence of pregnancy?

Answer 26

Yes

Question 27

What changes occur in the mammary glands during the first trimester?

Answer 27

Elongation and branching of smaller ducts | Proliferation of epithelial cells of glands and myoepithelial cells

Question 28

What changes occur in the mammary glands during the second trimester?

Answer 28

Glandular tissue continues to develop with differentiation of secretory alveoli Plasma cells and lymphocytes infiltrate nearby connective tissue

Question 29

What changes occur in the mammary glands during the third trimester?

Answer 29

Secretory alveoli continue to mature with development of extensive rER

Question 30

What are the changes that occur in the mammary gland during pregnancy accompanied by?

Answer 30

A reduction in the amount of connective and adipose tissue present

Question 31

What hormones stimulate proliferation of secretory cells in the mammary glands during pregnancy?

Answer 31

Oestrogen and progesterone

Question 32

What is the composition of milk produced by the humans?

Answer 32

``` 88% water 15% protein = mainly lactalbumin and casein 7% carbohydrate = mainly lactose 3.5% lipid Small amounts of ions, vitamins and IgA ```

Question 33

Are all compositions of milk secreted by the same mechanism?

Answer 33

No = two methods are apocrine and merocrine (exocytosis) secretion

Question 34

What occurs in apocrine secretion?

Answer 34

Lipid droplets are secreted surrounded by membrane and carrying a small amount of cytoplasm

Question 35

What occurs in merocrine secretion?

Answer 35

Proteins in milk are secreted via vesicles which may merge with apical membranes to release only their contents into the duct system

Question 36

What happens to the proteins in milk before they are released via merocrine secretion?

Answer 36

Made in the rER and packaged in the Golgi apparatus

Question 37

What changes occur in the breast during menopause?

Answer 37

Secretory cells of terminal lobular unit degenerate leaving only ducts

Question 38

What happens to the connective tissue of the breast during menopause?

Answer 38

There are fewer fibroblasts and reduced collagen and elastic fibres

Question 39

What occurs in ductal carcinomas?

Answer 39

Normal breast stroma has been invaded by malignant epithelial cells = ducts may be filled and expanded by cancerous growth