Lecture 1 Characteristics of Epithelial Tissues

Question 1

9 characteristics of Epithelial Tissues

Answer 1

Cells with relatively uniform geometric shape
Cells tightly bound together
Relatively little intercellular matrix
Cells exhibit polarity
Tissues do not contain blood vessels
Tissues sit on top of basal lamina
Tissues derived from -Ecto -Endo and Mesoderm
Line body cavities and cover body surfaces
Form secretory and excretory parts of glands

Question 2

Where do epithelial tissues get blood?

Answer 2

Mostly from connective tissue, do not contain blood vessels

Question 3

Epithelial Tissues derived from:

Answer 3

The 3 germ layers

1. Ecto
2. Endo
3. Meso

Question 4

Germ Layers

Answer 4

All tissue in adults come from the 3 layers
Ecto
Endo
Meso
Most come from ecto and endo. Some specialized from Meso.

Question 5

Where are Epithelial Tissues?

Answer 5

Line body cavities and cover body surfaces

Question 6

4 ways to classify epithelial

Answer 6

1. number of cell layers (simple, stratified)
2. shape (squamous, coboidal, columnar)
3. according to surface modifications on apical domain
4. keratinized or non-keratinized

Question 7

Simple

Answer 7

Single cell layer

Question 8

Stratified

Answer 8

2 or more cell layers

Question 9

Squamous

Answer 9

flattened cells

Question 10

Cuboidal

Answer 10

tall as they are long cells

Question 11

Columnar

Answer 11

much taller than they are wide cells

Question 12

Which cell layer do you look at when classifying it?

Answer 12

Only the top.

Question 13

If top cells don’t have nucleus they are

Answer 13

keratinized

Question 14

Keratinized stratified squamous example

Answer 14

Epidermis

Question 15

Cilia

Answer 15

long, filamentous that move back and forth
Organized by basal bodies:
-formed by 9 microtubule triplets in a helicoid array

Question 16

Stereocilia

Answer 16

Same as cilia but don’t move

Question 17

3 surface modifications on apical domains of outermost cell layer
(way to classify)

Answer 17

1. Cilia
2. Stereocilia
3. Microvilli (brush border)

Question 18

Microvilli

Answer 18

surface modification on apical domains 
Short filamentous, forms brush border
Core of Actin filaments
Anchored to terminal web made of other Actin cells
Cap controls how long they are

Question 19

Kerratinized

Answer 19

Way to classify epithelial tissues

top cells do not have nucleus

Question 20

Main function microvilli

Answer 20

Increase surface area and associated absorption.

Question 21

Ex of where stereocillia occur

Answer 21

Epididymis

Question 22

Pseudostratified

Answer 22

Type of simple
Single layer of cells, microscopically looks like two or more layers
Cells of varying height, all in contact with basement membrane

Question 23

Transitional

Answer 23

Type of simple? (some consider to be stratified)
Epithelium that is designed to be stretches.
Lines urinary bladder, ureters.

Question 24

2 parts of cell Polarity

Answer 24

1. Apical domains

2. Basolateral domains

Question 25

Apical domains

Answer 25

Characterized by surface modifications | Ex. cilia and microvilli

Question 26

Basolateral domains

Answer 26

Characterized by intercellular junctions | In contact with basement membrane

Question 27

Example of Simple Columnar cells

Answer 27

Intestinal cells

Question 28

Type of cells in thyroid

Answer 28

Simple cuboidal | Goes from high to low depending on function

Question 29

Non-keratinized

Answer 29

Or lightly keratinized May show presence of nuclei in outermost layers of cell Ex. esophagus and vagina

Question 30

Basement membrane consists of

Answer 30

Basal lamina that contains Laminin either entactin and proteoglycans Reticular lamina

Question 31

Basal Lamina

Answer 31

Part of basement membrane Produced by epithelium Contains: Entactin and Proteoglycans

Question 32

2 things Basal lamina contains

Answer 32

1. Laminin Entactin Proteoglycans

Question 33

Fibronectin

Answer 33

``` Made up of two protein chains cross-linked by disulfide bonds Has binding sites for: -Heparin -Integrins -Collagen -Fibrin ```

Question 34

Fibronectin 4 binding sites

Answer 34

1. Heparin 2. Integrins 3. Collagen 4. Fibrin

Question 35

Simple squamous examples

Answer 35

Lung air sacs Bowman's capsule Endothelium Mesothelium

Question 36

Simple cuboidal examples

Answer 36

``` Surface of ovary Pigmented epithelium of retina Kidney tubules Glands and ducts Terminal bronchioles Choroid plexus of brain ```

Question 37

Simple, non-ciliated columnar examples

Answer 37

Digestive tract from cardia of stomach Excretory ducts of many glands Gallbladder

Question 38

Simple, ciliated columnar examples

Answer 38

``` A few portions of upper respiratory tract Uterine tubes Uterus Paranasal sinuses Central canal of the spine ```

Question 39

Stratfifed squamous, non-keratinized or moderately keratinized examples

Answer 39

``` Lining of mouth Tongue Esophagus Part of epiglottis Vagina ```

Question 40

Stratified squamous, highly keratinized

Answer 40

Epidermis

Question 41

Stratified cuboidal examples

Answer 41

Seldom found

Question 42

Stratified columnar examples

Answer 42

Seldom found

Question 43

Stratified transitional examples

Answer 43

aka urothelium Lining of bladder Ureters Superior urethra

Question 44

Pseudostratified epithelium

Answer 44

Ciliated in respiratory system | Male reproductive system without cilia

Question 45

Pseudostratified examples

Answer 45

``` Large excretory ducts of many large glands Male urethra Eustachian tube Upper respiratory tract Some ducts of male reproductive system ```