Breast Histology

Question 1

Where is the breast in relation to the body wall?

Answer 1

Outside the body wall; not in the body wall

It’s a subcutaneous gland

Question 2

Approx how many lobes make up the secretory tissue of the breast?

Answer 2

15-25 lobes

Question 3

What type of gland is found in the lobes of the breasts?

Answer 3

Each lobe consists of a

compound tubulo-acinar gland

which drains via a series of ducts leading to the nipple

Question 4

What type of connective tissue surrounds the secretory lobules?

Answer 4

Dense fibrous tissue

which in turn is surrounded by adipose

Question 5

Between which two structures do suspensory ligaments of the breast extend?

Answer 5

from the dermis of the skin

to the deep fascia overlying the muscle of the anterior chest wall

Question 6

Where are the suspensory ligaments most pronounced?

What is their role thought to be?

Answer 6

Often most pronounced in the upper breast

Thought to support the breast tissue

Question 7

What is clinically relevant about the suspensory ligaments of the breast?

Answer 7

because when breast becomes oedematous or inflamed

there’s essentially nowhere for excess pressure to go (because all essentially surrounded by connective tissue)

which will change surface of breast as a result and clinically will see changes on surface of breast

Question 8

What is the basic functional secretory unit of the breast?

Answer 8

The Terminal Duct Lobular Unit (TDLU)

Question 9

Explain the route of the non-lactating breast from the terminal ductules

Answer 9

Terminal ductules –> intralobular collecting duct –> lactiferous duct for that lobe –> nipple –> passes through lactiferous sinus (an expanded duct region near the nipple)

Question 10

What kind of epithelial cells line the acini?

Answer 10

Cuboidal

and columnar

Question 11

Describe myoepithelial cells

Answer 11

The secretory cells of the acinus are surrounded my myoepithelail cells

They are contractile epithelial cells wich in turn are surrounded by the basal lamina

Question 12

Which cells surround the secretory cells of the acinus?

Answer 12

Myoepithelial cells

Question 13

Which cells line the lactiferous duct?

Answer 13

The lacteriferous ducts are lined by an epithelium that varies from a thin stratified squamous to stratified cuboidal

Question 14

What cells cover the nipple?

Answer 14

A thin highly pigmented keratinsed stratified squamous epithelium

Question 15

What is the core of the nipple made up of?

Answer 15

dense irregular connective tissue mixed with bundles of smooth muscle

Question 16

Regarding the lactiferous duct where do you find stratified sq. epithelium and where do you find stratified cuboidal epithelium?

Answer 16

As the duct approaches the surfaces it becomes lined by stratified squamous epithelium,

however deeper it is lined by stratified cuboidal epithelium

(see image a)

Question 17

What happens to mammary glands during the luteal phase of the menstrual cycle?

Answer 17

The epithelial cells increase in height

the lumina of the ducts becomes enlarged

and small amounts of secretions appear in the ducts

Question 18

What changes happen to the mammary gland in the first trimester of pregnancy?

Answer 18

elongation and branching of the smaller ducts

proliferation of the epithelial cells of the glands and the myoepithelial cells

Question 19

What changes happen in the mammary gland in the second trimester?

Answer 19

glandular tissue continues to develop with differentiation of secretory alveoli

plasma cells (produces IgA; important for colustrum) and lymphocytes infiltrate the nearby connective tissue

Question 20

What changes happen in the mammary gland in the third trimester of pregnancy?

Answer 20

alveoli continue to mature

development of extensive rER

Question 21

What changes happen over the three trimesters of pregnancy?

Answer 21

Reduction in amount of connective tissue

Reduction in amount of adipose tissue present

Question 22

Which hormones stimulate proliferation of secretory tissue?

Answer 22

Oestrogen

Progesterone

Question 23

What is human milk composed of?

Answer 23

88% water

1.5% protein (mainly lactalbumin and casein)

7% carbohydrate (mainly lactose)

3.5% lipid

with small quantities of ions, vitamins and IgA antibodies

Question 24

“Different components of milk are secreted via different mechanisms”

T/F

Answer 24

True

Different components of milk ARE secreted via different mechanisms

Question 25

Which method of secretion are lipid droplets secreted by?

Answer 25

Apocrine secretion

Question 26

Describe apopcrine secretion

Answer 26

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

Question 27

Which method of secretion are the proteins in milk secreted by?

Answer 27

Merocrine secretion (a.k.a. exocytosis)

Question 28

Describe merocrine secretion

What other name can be used to describe it?

Answer 28

vesicles merge with the apical membrane to release their contents (into the duct system)

a.k.a exocytosis

Question 29

What happens to the secretory cells of the TDLU following menopause?

Answer 29

they degenerate leaving only ducts

Question 30

What happens to the connective tissue of the TDLU following menopause?

Answer 30

There are fewer fibroblasts and reduced collagen and elastic fibres