Epithelium

Front 1

In general, what does epithelium do?

Back 1

1. Covers surfaces and lines cavities

2. Secretes as glands

3. Functions as receptors

Front 2

What are exceptions to areas that don't contain epithelium?

Back 2

1. Articular cartilage

2. Tooth enamel

3. Anterior iris

Front 3

How are epithelial types based?

Back 3

On cell shape and cell layers

Front 4

How many layers composes simple epithelium?

Back 4

One (singular)

Front 5

How many layers composes stratified epithelium?

Back 5

Two or more

Front 6

How many layers composes pseudostratified epithelium?

Back 6

It's a single layer of cells with different heights that all touch the basement membrane, but don't all reach the lumen.

Front 7

What are the functions of simple squamous epithelium?

Back 7

1. Diffusion

2. Filtration

3. Gas Exchange

Front 8

Where is simple squamous epithelium found?

Back 8

1. Kidney filtration membrane

2. Lung alveoli

3. Endothelium/Mesothelium

Front 9

Which cell types function for secretion and absorption?

Back 9

1. Simple Cuboidal Epithelium

2. Simple Columnar Epithelium

3. Pseudostratified

4. Transitional/Urothelium (stretchy)

Front 10

Where are simple cuboidal cells found?

Back 10

1. Small glandular ducts

2. Kidney tubules

3. Thyroid (follicular cells)

Front 11

Where are simple columnar cells found?

Back 11

1. Large ducts

2. GI tract (microvilli, goblets)

3. Respiratory Tract (cilia)

Front 12

Where are pseudostratified epithelial cells found?

Back 12

1. Large ducts

2. Male reproductive system

3. Respiratory and urinary tracts

Front 13

What is the function of stratified squamous epithelium?

Back 13

Protection

Front 14

What are the locations of stratified squamous cells?

Back 14

1. Keratinized regions (epidermis)

2. Nonkeratinized regions (mouth, esophagus, vagina)

Front 15

Keratinized stratified squamous epithelium

Back 15

1. Apical layers have the most differentiated, least viable cells

2. Nuclei undergo pyknosis as migrate north

3. Keratin offers protection from chemicals/physical injury. Prevents water loss

Front 16

Nonkeratinized stratified squamous epithelium

Back 16

Have viable apical cells with nuclei.

Front 17

Where keratinized stratified squamous epithelia is found

Back 17

The epidermis

Front 18

Where nonkeratinized stratified squamous epithelia is found

Back 18

Mouth, esophagus and vagina

Front 19

How to tell the difference between nonkeratinized stratified squamous epithelium and distended urothelium

Back 19

1. Layers of differentiation

2. Number of layers

3. Nuclei shape

4. Basement Membrane

Front 20

Where is stratified cuboidal epithelia found?

Back 20

Sweat gland ducts, and mammary gland ducts

Front 21

Where is stratified columnar epithelia found?

Back 21

Conjunctiva, large ducts, male urethra, pharynx

Front 22

Components of Parenchyma

Back 22

1. Secreteory Ducts

2. Ducts

3. Stroma

Front 23

What is stroma?

Back 23

Supportive connective tissue surrounding the parenchyma

Front 24

These types of glands have ducts and secrete non-hormonal fluids

Back 24

Exocrine glands

Front 25

These glands do not have ducts, are very vascular, and secrete hormones

Back 25

Endocrine glands

Front 26

What are examples of exocrine glands?

Back 26

Salivary glands

Front 27

What are examples of endocrine glands?

Back 27

Adrenal, thyroid

Front 28

What are ways to classify glandular epithelium?

Back 28

1. Timing, nature, mode, and distance traveled by secretion

2. Cell number

Front 29

How is timing of secretion of glandular epithelium classified?

Back 29

Constituitive vs. regulated

Front 30

What are the methods by which secretions can travel?

Back 30

1. Autocrine (platelets)

2. Paracrine (testes)

3. Endocrine

4. Exocrine

Front 31

What is meant by the nature of secretion?

Back 31

1. Serous (clear, proteins, zymogen granules)

2. Mucous (rich in GPs, PAS+)

3. Mixed (demilunes)

4. Hormone

Front 32

What are the modes of secretion?

Back 32

1. Merocrine (Exocytosis)

2. Apocrine (Goblets, mammary)

3. Holocrine (Sebum)

Front 33

What are key traits of epithelia?

Back 33

1. High cell:ECM

2. Avascularity

3. Regenerative

4. Derived from all 3 germ layers

Front 34

What are the polar domains of epithelial cells?

Back 34

Apical, basal, and 2 lateral domains

Front 35

Apical Domain

Back 35

1. Faces the lumen/air

2. Has glycocalyx, is motile (cilia/flagella)

3. Increases surface area (cilia/villi)

Front 36

Basal Domain

Back 36

1. Faces basement membrane

2. Hemidesmosomes attach to CT

3. Plasma membrane infoldings (increase surface area, ion transport)

Front 37

Lateral Domain

Back 37

1. Faces adjacent cell neighbors

2. Includes cell junctions and cell adhesion molecules

Front 38

How are epithelial interactions and cohesion maintained?

Back 38

By cell junctions and cell adhesion molecules

Front 39

What are the cell junctions?

Back 39

1. ZO

2. ZA

3. MA

4. Gap Junction

5. Hemidesmosome (basal)

Front 40

What are the cell adhesion molecules of the zonula occludens?

Back 40

1. Claudins/Occludins

2. JAMs

3. Nectin

Front 41

What are the cell adhesion molecules of the zonula adherins?

Back 41

Cadherins and nectin

Front 42

What are the cell adhesion molecules of the macula adherins?

Back 42

Cadherins

Front 43

What are the cell adhesion molecules of gap junctions?

Back 43

Connexins

Front 44

What are the cell adhesion molecules of hemidesmosomes?

Back 44

Integrins

Front 45

What are the characteristics of the zonula occludens layer?

Back 45

1. Most apical

2. Tight junction. Tight belt/ziplock (cell-cell)

3. Occludin, claudin, JAM, ZO, actin

4. Intestinal epithelium. Passive but selective diffusion

Front 46

What are the characteristics of the zonula adherens layer?

Back 46

1. Anchoring junction "anchoring belt", cell-cell

2. Snapback cap (laterally encircles cell)

3. Cadherins interact with catenins plaque to link to actin

4. Fascia adherins in cardiac intercalated discs

Front 47

What are the characteristics of the macula adherens layer?

Back 47

1. Anchoring junction "anchoring spot", cell-cell

2. Cadherins interact with plaque to link to Keratin

3. Prickle cells

Front 48

What are the characteristics of gap junctions?

Back 48

1. Communciation junction (cell-cell)

2. Connexins (6/channel)

3. Epithelium, cardiac muscle, smooth muscle, neurons

Front 49

What are the characteristics of hemidesmosomes?

Back 49

1. Anchoring Junction (1/2 snap)

2. Plakins bind Keratin and Integrin

3. Integrin anchors Cell:ECM/BL

Front 50

Is epithelia vascular?

Back 50

No.

Nutrients and wastes are exchanged by diffusion.

Exception = Stria vascularis of inner ear

Front 51

Is epithelia metaplastic?

Back 51

Yes.

Front 52

In which cases does epithelium regenerate?

Back 52

1. Skin and intestines

2. Wound repair

3. Cancer

Front 53

What germ layers does epithelia originate?

Back 53

Ectoderm, endoderm, and mesoderm.

Front 54

What epithelial areas serve to protect?

Back 54

Epidermis and mucus

Front 55

What epithelial areas serve for transport?

Back 55

1. Cilia (surface)

2. Membranes for in/out cell transport

3. Glands : Secretion :: Wastes : Excretion

4. Microvilli (Absorption)

5. Alveoli (Gas Exchange)

Front 56

A) What components of epithelia serve to provide selective permeability?

B) Where?

Back 56

A. Cell junctions

B. Intestines and BBB

Front 57

What area of epithelium serves to reduce surface friction?

Back 57

Mesothelium

Front 58

What area of epithelium serves to provide sensations?

Back 58

Taste buds

Front 59

What area of epithelium is an example of the distensibility feature?

Back 59

Urinary bladder