Epithelia

Question 1

What are the embryonic origins of epithelia

Answer 1

Ectoderm mesoderm and endoderm

Question 2

What tissues come from ectoderm

Answer 2

Ectoderm forms skin mouth nose anus and nervous tissue

Question 3

What tissues come from mesoderm

Answer 3

Mesoderm forms lymphatic lining and muscle tissue

Question 4

What tissues come from endoderm

Answer 4

Endoderm forms airway and digestive system lining

Question 5

What is epithelia

Answer 5

Tissue that covers and lines internal and external body surfaces

Question 6

How is epithelia classified

Answer 6

By cell shape and stacking arrangement

Question 7

Describe simple squamous epithelium

Answer 7

Single flat layer with flattened nuclei for diffusion

Question 8

Where is simple squamous epithelium found

Answer 8

Alveoli blood vessels

Question 9

Describe simple cuboidal epithelium

Answer 9

Single cube-shaped cells with central nuclei

Question 10

Where is simple cuboidal epithelium found

Answer 10

Renal tubules nephron lining thyroid follicles

Question 11

Function of simple cuboidal epithelium

Answer 11

Secretion and absorption

Question 12

Describe simple columnar epithelium

Answer 12

Single tall columnar cells with basal nuclei

Question 13

Where is simple columnar epithelium found

Answer 13

Digestive tract fallopian tubes respiratory tract

Question 14

Function of simple columnar epithelium

Answer 14

Secretion and absorption

Question 15

What defines stratified squamous epithelium

Answer 15

Top layer of squamous cells bottom layers vary

Question 16

Function of stratified squamous epithelium

Answer 16

Protects against abrasion

Question 17

Types of stratified squamous epithelium

Answer 17

Keratinised and non-keratinised

Question 18

What is keratinisation

Answer 18

Process where cells accumulate keratin and become dead and tough

Question 19

Function of keratinised epithelium

Answer 19

Provides mechanical strength and barrier to dehydration

Question 20

Where is non-keratinised epithelium found

Answer 20

Oral cavity conjunctiva rectum vagina

Question 21

What is pseudostratified epithelium

Answer 21

Single layer appearing stratified due to nuclear position

Question 22

Where is pseudostratified epithelium found

Answer 22

Bronchi trachea

Question 23

What is transitional epithelium

Answer 23

Stratified epithelium that changes shape when stretched

Question 24

Where is transitional epithelium found

Answer 24

Bladder ureters

Question 25

Function of transitional epithelium

Answer 25

Allows stretch depending on urine volume

Question 26

What is glandular epithelium

Answer 26

Epithelia that invaginates into tissue to form glands

Question 27

Examples of glandular epithelium

Answer 27

Sebaceous mammary salivary glands

Question 28

What additional cell is found in glandular epithelium

Answer 28

Goblet cells

Question 29

Common features of epithelial cells

Answer 29

Cellularity cell junctions polarity basement membrane

Question 30

What is cellularity in epithelium

Answer 30

Epithelia are made entirely of cells forming a barrier

Question 31

Function of tight junctions

Answer 31

Prevent leakage and force substances through cells

Question 32

Where are tight junctions important

Answer 32

Blood brain barrier gut epithelium seminiferous tubules

Question 33

What are anchoring junctions

Answer 33

Strong mechanical attachments using cadherin proteins

Question 34

What do cadherins require to function

Answer 34

Calcium ions in extracellular space

Question 35

What are adherens junctions

Answer 35

Anchoring junctions connected to actin filaments

Question 36

What do adherens junctions form

Answer 36

Continuous adhesion belt near apical end

Question 37

What is the function of adherens junctions

Answer 37

Provide mechanical stability to epithelial sheets

Question 38

What are desmosomes

Answer 38

Anchoring junctions linked to keratin intermediate filaments

Question 39

What is the intracellular structure of desmosomes

Answer 39

Cadherin binds to cytoplasmic plaque and keratin filaments

Question 40

What is the function of desmosomes

Answer 40

Provide tensile strength across epithelial cells

Question 41

What disease is linked to desmosome dysfunction

Answer 41

Pemphigus causing blistering

Question 42

What are hemidesmosomes

Answer 42

Cell to basal lamina junctions built with integrins

Question 43

What is the role of integrins in hemidesmosomes

Answer 43

Link keratin filaments to basal lamina

Question 44

What is a gap junction

Answer 44

Water filled channel formed by connexons between cells

Question 45

What is the function of gap junctions

Answer 45

Allow ion and small molecule passage for communication

Question 46

Where are gap junctions important

Answer 46

Cardiac muscle retina pancreas ciliary epithelium

Question 47

What are connexons made of

Answer 47

Six connexin subunits forming a pore

Question 48

How are gap junctions regulated

Answer 48

By voltage pH and signalling molecules

Question 49

What is cell polarity

Answer 49

Asymmetry with distinct apical and basal surfaces

Question 50

What specialisations are found at the apical surface

Answer 50

Cilia and microvilli

Question 51

What is the basement membrane

Answer 51

ECM layer beneath epithelial cells

Question 52

Components of the basement membrane

Answer 52

Type IV collagen laminin perlecan

Question 53

Functions of the basement membrane

Answer 53

Support regulate molecule movement attach epithelium to connective tissue

Question 54

What is a general feature of epithelia

Answer 54

No extracellular material cells joined by junctions avascular

Question 55

Functions of epithelial tissues

Answer 55

Protection absorption secretion dialysis sensation

Question 56

What is a neoplasm

Answer 56

Tumour due to loss of growth control

Question 57

What is carcinoma

Answer 57

Malignant tumour from epithelial cells

Question 58

What is squamous carcinoma

Answer 58

Malignant tumour from squamous epithelium

Question 59

What is adenocarcinoma

Answer 59

Malignant tumour from glandular epithelium