Epithelial Tissues

Question 1

What are epithelial tissues?

Answer 1

Lining tissues that cover all internal and external body surfaces

Eg tissues, tubes, cavities

Question 2

Give 3 examples of systems epithelial tissues line?

Answer 2

Digestive
Respiratory
Cardiovascular

Question 3

2 common features of epithelial tissues?

Answer 3

Barrier function - all substances entering/leaving body must pass through

Form continuous boundary between different environments

Question 4

How are epithelial cells arranged?

Answer 4

Continuous sheets of tightly bound cells with connective tissues Underlying to give nutrients

Question 5

Why does connective tissues underlay epithelial cells?

Answer 5

To provide nutrients

Question 6

What do epithelial cells help to control?
What does this prevent?

Answer 6

What substances enter and leave cell therefor prevent microbial invasion

Question 7

Name the 3 surfaces of epithelial cells?

Answer 7

Apical

Lateral

Basal

Question 8

Describe a tight junction.
What is it’s purpose?

Answer 8

Creates impermeable seal between adjacent cells

Prevents water passage

Question 9

Describe desmosomes.

Answer 9

Strong junctions that anchor adjacent cells together.

Question 10

What do desmosomes ensure?

Answer 10

Epithelial cells can stretch while maintaining contact.

Question 11

What is the structure of epithelial cells?

Answer 11

Continuous sheets of cells
Tightly bound together
Polarised

Question 12

Function of epithelial tissues?

Answer 12

Cover and line all surfaces
Form a barrier

Question 13

Name 4 specialised functions of epithelial tissues.

Answer 13

Protection
Diffusion
Absorption
Secretion

Question 14

What is the least metabolically active shape of epithelial tissue?
Describe it.

Answer 14

SQUAMOUS

flat thin scale like cells

Has passive diffusion of cells through the epithelial layer.

Question 15

Name the 3 mains shapes of epithelial tissue.
What is the 4th?

Answer 15

Squamous
Cuboidal
Columnar

Transitional

Question 16

What does simple epithelium mean?

Answer 16

Single layer of cells

Question 17

What does stratified epithelium mean?

Answer 17

2 or more layers of cells

Question 18

What does pseudostratified mean?

Answer 18

One layer by appears stratified
Nuclei are at different heights
Cillia present on apical surface

Question 19

Describe transitional epithelial cells.

Answer 19

Mix all tall and flat cells
Stratified
Only found in bladder - allow for stretch and recoil

Question 20

Name 3 apical specialisations.

Answer 20

Microvilli
Cillia
Keratin

Question 21

What are microvilli?

Answer 21

Small finger like projections that extend into lumen
Found where function is absorption
Increase apical surface area

Question 22

What is Cillia?

Answer 22

Long hair like projections that best rhythmically to move matter along apical surface
Found where mucous secretions take place
Movement of particular matter

Question 23

What is keratin?

Answer 23

Strong protective apical layer
Strong interlinked protein
Involved in water proofing and protection

Question 24

What is the function and location of a simple squamous epithelium?

Answer 24

Function: lines all surfaces involved in passive diffusion (facilitated diffusion)
No energy required

Location:
lungs (alveoli)
Capillaries (endothelium)

Question 25

Describe the function and location of simple cuboidal epithelia.

Answer 25

Function: line small ducts and tubules involved in absorption/secretion

More metabolically active so bigger to support active function

Location:
renal tubules (absorption)
Salivary glands (secretion)

Question 26

Describe the function and location of simple columnar epithelium.

Answer 26

Function: lines absorptive surfaces
Thicker so has more protection

Location: small intestine (microvilli present

Question 27

What do microvilli do on simple columnar epithelium?

Answer 27

microvilli increase surface area which helps to facilitate absorbing nutrients

Question 28

Describe simple columnar ciliated.
Function and location

Answer 28

Function: ciliary action facilitated transport of ovum from ovary to uterus

Location: female reproductive tract

Question 29

Describe pseudo-stratified columnar ciliated.
Function and location

Answer 29

Function: ciliary action propel surface layer of mucus containing trapped particles towards pharynx.

Location: always of respiratory system

Position of nucleus is different

Question 30

What is a goblet cell?

Answer 30

-Modified columnar epithelium
-Synthesise and secrete mucous
-Scattered throughout simple columnar epithelial cell (respiratory/ GIT)
-packed with mucins
- Don’t have cilia

Question 31

Describe stratified cuboidal epithelium.
Function and location

Answer 31

Function: secretory (have more protection than simple/ more robust

Location: RARE some secretory glands and ducts

Question 32

Describe stratified columnar epithelium.
Function and location.

Answer 32

Function: secretory & protective

Location: RARE male urethra and lining some glands

Question 33

Describe features of a stratified squamous epithelium.

Answer 33

• found where function is to protect against mechanical abrasion
• cells migrate to surface and are shed as anucleate squames

Question 34

Stratified squamous epithelia can be nonkeratinised or keratinised on apical surface.
What does keratin do?

Answer 34

Enhances resistance to physical stress

Accumulate keratin filaments as they mature

Tough, non living surface layer that cross links so doesn’t shed

Question 35

What does transitional epithelium do?

Answer 35

It allows for expansion and stretch

Found only in bladder

Flat when stretched
Tall when relaxed

Question 36

What is caused by a break in the continuity of epithelium?

Answer 36

Ulceration
Caused by herpes

Targets cuboidal cells at bottom

No access unless there is damage to top of epithelium cells

Question 37

What is an oral squamous cell carcinoma?

Answer 37

Dysplastic (abnormal) epithelial cells proliferate in an uncontrolled manner

Destroy/ invade adjacent cells

Attacked by immune system

Suggests cancer