Epithelial tissue and the Mammary Gland

Question 1

3 ways epithelial tissue differs from other basic tissues

Answer 1

1. Closely adhering with little ECM
2. Avascular
3. High mitotic index

Question 2

4 functions of epithelial tissue

Answer 2

Protection
Transport
Absorption
Synthesis and secretion

Question 3

2 criteria to classify epithelia

Answer 3

How many layers of cells?

What is the shape of the cell on the apical surface?

Question 4

Where do you find simple

1. squamous
2. cuboidal
3. columnar

Answer 4

1. blood vessels and body cavities
2. collecting ducts of kidneys
3. gallbladder

Question 5

Where do you find stratified

1. squamous non-keratinized
2. squamous keratinized
3. cuboidal
4. columnar

Answer 5

1. upper and lower GI (ex: epiglottis)
2. thin and thick skin
3. large ducts (sweat and esophageal glands)
4. points of transition (epiglottis, recto-anal junction)

Question 6

Pseudostratified epithelium

Answer 6

Single layer with nuclei at different heights

Upper respiratory tract (like auditory tube)

Question 7

Transitional epithelium

Answer 7

Multilayered
Appearance changes with physiological state
Bladder
When empty (contracted), there are 5-7 layers, round umbrella cells
When full (distended) there are 2-3 layers, flat umbrella cells

Question 8

What does the basement membrane stain best with?

Answer 8

Periodic acid-Schiff stain

Question 9

4 groups of proteins in the basement membrane

Answer 9

Glycoproteins
Linker proteins
Collagens
Proteoglycans

Question 10

Basement membrane vs basal lamina

Answer 10

BM: what you see under light microscope
BL: what you see under EM

Question 11

3 functions of basement membrane

Answer 11

Attach epithelium to CT
Selective barrier
Controls epithelial cell differentiation in growth and tissue repair

Question 12

2 types of tissues in glands

Answer 12

Parenchyma (epithelial tissue that forms the functional unit of glands - secretory cells and ducts)
Stroma (CT that forms the supportive unit of glands)

Question 13

Fetal stage in mammary gland development

Answer 13

Milk line develops from axilla to groin, followed by regression except in pectoral region
15-25 cords invade stroma
Rudimentary duct system present at birth

Question 14

Puberty stage in mammary gland development

Answer 14

Period of rapid growth
Due to establishment of ovarian cycle and increased level of estrogen and progesterone
Main ducts elongate, branch and end in terminal end buds
Gland size increases largely due to deposition of adipose tissue

Question 15

Adult/resting stage in mammary gland development

Answer 15

Compounding development occurs with each ovarian cycle until about 35 yo
Ducts elongate and branch with 2 layers of cells
Terminal ducts form clusters called lobules

Question 16

2 layers of cells in the terminal end buds

Answer 16

Cuboidal epithelial inner layer

Myoepithelial outer layer

Question 17

Pregnancy/lactation stage in mammary gland development

Answer 17

Estrogen/progesterone/prolactin transform breast into mature organ with further ductal branching and alveolar morphogenesis
2 cell types
Lactation begins 48-72 hours after birth due to decrease in progesterone and increase in prolactin

Question 18

Post lactational involution

Answer 18

Weaning stimulates alveolar apoptosis and involution back to resting state

Question 19

Post menopausal involution

Answer 19

Cessation of ovarian cycle leads to a further drop in ovarian hormones, a greater loss of glandular tissue, and an increase in adipose tissue

Question 20

Carcinoma

Answer 20

Cancer of the epithelium

Question 21

Metaplasia

Answer 21

Replacement of one epithelium with another that is normal in appearance
Cells can reverse to other type with the removal of the stress

Question 22

Dysplasia

Answer 22

Same epithelium but cells look different and epithelium is disorderly

Question 23

3 cell types in respiratory epithelium

Answer 23

Stem cells
Goblet cells
Tall columnar ciliated cells

Question 24

How do you describe the shape of ducts in glands?

Answer 24

Simple (no branches)

Compound (branched)

Question 25

How do you describe the shape of secretory portions in glands?

Answer 25

Tubular
Acinar
Tubuloacinar

Question 26

Merocrine glands

Answer 26

Use exocytosis

Ex: salivary gland, pancreas, mammary gland protein secretion

Question 27

Apocrine glands

Answer 27

Release of a small portion of the apical cytoplasm

Ex: mammary gland lipid secretion

Question 28

Holocrine glands

Answer 28

Disintegration of cell and release of product

Ex: sebaceous glands

Question 29

Serous demilune

Answer 29

Moon shaped cap of serous cells on some mucous acini

Question 30

4 stages of breast cancer progression

Answer 30

Normal
Atypical ductal hyperplasia
Ductal carcinoma in situ
Invasive ductal carcinoma

Question 31

Atypical ductal hyperplasia

Answer 31

First step towards breast cancer
Ductal epithelial cells proliferate and can eventually fill the ducts
There can be regular spaces that appear as “punched out holes”
Cell size, shape and nuclei also look different (cellular atypia)

Question 32

Ductal carcinoma in situ

Answer 32

Second step towards breast cancer
Ducts are filled with atypical epithelia and many have central areas of necrosis
Nuclei are large and irregular
No invasion into the stroma

Question 33

Invasive ductal carcinoma

Answer 33

Most common type of invasive breast carcinoma
Ductal carcinoma cells extend through the stroma and incite a fibrotic reaction
Malignant cells have enlarged
Irregular nuclei with nucleoli