EPITHELIA

Question 1

What are the two types of epithelia

Answer 1

Surface epithelia that lines the surfaces of internal and external surfaces of the body

Glandular epithelia epithelial cells involved in secretion

Question 2

What supports all epithelial cells? what is its function

Answer 2

Basement membrane

separates epithelia from underlying connective tissue
Brings blood and nervous innervation close to epithelia

Question 3

Why is it Polarity important in simple cuboidal and simple columnar epithelium

Answer 3

allows the cells to have asymmetry which allows specific receptor proteins and transport proteins to be present on different sides of the cell. As such all epithelial cells have an apical and basal side

Question 4

What are the two layers of the basement membrane

Answer 4

Basal lamina comprised of mainly collagen one to which epithelial cells directly anchor
Reticular lamina thicker layer of reticular fibres

Question 5

What is the difference between simple, stratified and psudostratified epithelium

Answer 5

Simple: all cells have direct contact with basement membrane single layer

Stratified: multiple layers of cells. Only deepest cell layer has connection with basal lamina

Psudostratified: single layer of irregularly shaped cells all with direct contact with the basement membrane

Question 6

How do you classify epithelial tissue?

Answer 6

First simple stratified psudostratifed
Then classify by shape squamous columnar transitional
Then add ending epithelium

Question 7

Where can you find simple squamous epithelium

Answer 7

Alveoli
walls of capillaries (endothelium)

Not resistant to abrasion allows rapid diffusion absorption secretion

Question 8

Where would one find simple cuboidal epithelium

Answer 8

Collecting tubules of kidney

Thyroid follicle cells

Question 9

What are characteristics of simple cuboidal epithelium

Answer 9

Nucleus contrarily located
Box shaped in contact with approximately 6 other cells
Found on secretory and absorptive surfaces

Question 10

Where in the body can you find simple columnar epithelium?

Answer 10

small intestine

stomach

Question 11

What are key identifiable features of simple columnar epithelium?

Answer 11

cells taller than they are wide

nucleus more basaly located

Question 12

How are stratified epithelium classified?

Answer 12

On shape of outermost cell

Question 13

What are the characteristics of stratified squamous epithelium

Answer 13

more resistant to friction and abrasion

layer in contact with basement membrane active mitosis and cell division

Question 14

Where can you find stratifies squamous epithelium

Answer 14

Vagina
oesophagus
oral cavity

Question 15

What is keratinised stratified squamous epithelium

Answer 15

Keratinised cells
Further protection to withstand abrasion and from a protective waterproof barrier
Skin

Question 16

What is transitional epithelium?
Where is it located
Adaptations

Answer 16

Cell shape changes
Stratified not all cells in contract with basal lamina
Found in the urinary tract e.g. bladder
Allows cells to stretch and change shape and withstand high toxicity of urine

Question 17

What are some tissue specialisations?

Answer 17

Villi increase surface area for absorption
Cilla beat rhythmically to waft mucus
Goblet cells produce and secrete mucus

Question 18

What is ciliated psudostratified epithelia with goblet cells

Answer 18

found in upper respiratory tract
acts to trap pathogens and dust particles preventing them entering the lungs
cilia beat to prevent stagnation waft mucus up to mouth swallowed

Question 19

What are the most apical junctions in cells?

Answer 19

Tight junction Zona occludens
super-tight impermeable junctions prevent movement of proteins on cell surface and ions between cells
all ions and molecules must pass through the cell

Question 20

What is the zona adherens what is there function

Answer 20

Belt desmosomes

located just below tight junctions involved in cell to cell anchoring and stability

Question 21

What is the macula adherens

Answer 21

Spot desmosomes

ack like wielding points between cells

Question 22

What are gap junctions?

Answer 22

formed from 6 connexins on each side of the membrane joining together to from a connexion which then lign up to form a channel

An electrical synapse allow for electrical continuity between cells through movement of ions

Question 23

What are hemidesmosomes

Answer 23

Junction through which epithelial cells attaches to the basal lamina

Question 24

What does carcinoma mean?

Answer 24

form of cancer that originates in epithelia tissue

Question 25

What is dysplasia

Answer 25

abnormal growth of cells within a tissue

is not cancer but may develop to be

Question 26

What is metaplasia

Answer 26

change in cell type in a tissue from normal to another cell type

Question 27

What is Barrett’s oesophagus?

Answer 27

Metaplasia of cells in oesophagus just above the stomach.

Change from normal stratified squamous epithelium to simple columnar epithelium

Question 28

What is neoplasia?

Answer 28

abnormal uncontrolled growth of cells resulting int he formation of a tumour (metaplasia and dysplasia may develop to be this)

Malignant neoplasms are simple called carcinomas

Question 29

What disease are common tested for using epithelial cell smears

Answer 29

cervical cancers