Epithelium I

Question 1

What is epithelial tissue?

Answer 1

A group of tissues found covering the body

Question 2

What is epithelial tissue made up of?

Answer 2

Closely packed cells in 1 layer or multilayers

Question 3

What is epithelium derived from?

Answer 3

Embryo germ layers

Question 4

How many embryo germ layers do humans have?

Answer 4

• 3
  1. Endoderm
  2. Mesoderm
  3. Ectoderm

Question 5

What is endoderm?

Answer 5

the inner layer that provides lining for digestive and respiratory tubes

Question 6

What is mesoderm?

Answer 6

Middle layer where the bodys organs are found

Question 7

What is the ectoderm?

Answer 7

Outer layer which gives rise to the skin

Question 8

What are the functions of epithelium?

Answer 8

• protect underlying tissues from injury
• prevent bacterial invasion
• prevent loss of fluid from underlying tissues

Question 9

Describe the structure of epithelium?

Answer 9

• cells closely packed together
• intercellular stubsance (matrix) is minimal
• cells lie on basement membrane
• receive nourishment from underlying connective tissue

Question 10

What are the different types of epithelium?

Answer 10

• simple (single layer of cells)
• stratified (several layers of cells)

Question 11

What are the different types of simple epithelium ?

Answer 11

• squamous
• cuboidal
• columnar
• cilliated

Question 12

Where can simple epithelium be found?

Answer 12

Usually on absorptive or secretory surfaces, not usually areas subject to stress

Question 13

Describe simple squamous epithelium?

Answer 13

• single layer of flattened cells
• fit closely together forming a smooth inactive lining

Question 14

Where can simple squamous epithelium be found?

Answer 14

• blood vessels
• alveoli of the lungs

Question 15

What is the structure of simple cuboidal epithelium?

Answer 15

• cube shaped cells
• fit closely together lying on a basement membrane

Question 16

What is the function of simple cuboidal epithelium?

Answer 16

involved in secretion, absorption & excretion

Question 17

What does simple cuboidal epithelium form?

Answer 17

Kidney tubules and some glands

Question 18

Describe simple columnar epithelium

Answer 18

• single layer elongated cube shaped cells
• height is greater than width
• lies on basement membrane

Question 19

What is the function of simple columnar epithelium?

Answer 19

• lines organs of alimentary tract and ducts of some glands
• some absorb products of digestion, others secrete mucous

Question 20

What kind of specialised columnar epithelium secretes mucus?

Answer 20

Goblet cells

Question 21

What kids of epithelium are salivary glands?

Answer 21

Salivary glands are columnar epithelium

Question 22

What is the function of cilia on ciliated columnar epithelium?

Answer 22

On free surfaces of cells, cilia are fine hair like process have a beating action in one way to propel contents of a tube

Question 23

What is the function of ciliated epithelium?

Answer 23

moves particles or fluid over the epithelial surface

Question 24

What is a hemi- desmosome

Answer 24

specialised junctioning complexes which allows cells to join to eachother

Question 25

Where are hemi desmosomes found?

Answer 25

- Within the cell membrane of epithelial cells - also found between epithelial cells and connective tissue cells

Question 26

Once cells have adhered to eachother what are they called

Answer 26

Desmosomes

Question 27

What do hemi desmosomes contain?

Answer 27

Tonofilbrils which cause thickening of the cell wall

Question 28

What is the primary function of stratified epithelium?

Answer 28

To protect underlying structures

Question 29

Describe the structure of stratified squamous epithelium?

Answer 29

Consists of different layers with the deepest layer continually multiplying and the cells of the surface shedding

Question 30

What is an example of stratified squamous epithelium

Answer 30

Skin & mucous membranes

Question 31

What are the. 2 types of stratified squamous epithelium?

Answer 31

Keratinised and non-keratinised

Question 32

What are the names of the layers in keratinised stratified squamous epithelium?

Answer 32

- basal - prickle - granular - keratin

Question 33

Describe the basal layer of epithelium

Answer 33

- single layer of cells at base which repeatedly divide - push cells up towards surface - finger like projections of connective tissue extend into epithelium

Question 34

What happens to the basal layer in areas of greater friction?

Answer 34

The basal layer folds to increase the surface area, forming rete ridges

Question 35

Describe the prickle cell layer

Answer 35

- cells change from cuboidal to polyhedral - several layers of polyhedral cells present - prickles are formed by desmosomes

Question 36

Describe the granular layer of epithelium

Answer 36

- 1-5 layers of flattened polyhedral cells - contains granules in cytoplasm

Question 37

Describe the keratin layer of epithelium?

Answer 37

- outer layer of flattened cells remnants replaced by cells from below which have lost nucleus (sqaumes)

Question 38

Describe non-keratinised squamous epithelium

Answer 38

- granular and keratin layer are absent - prickle layer cells become flattened - outer layer of cells cont. shed