epithelial tissues

Question 1

what are the 4 types of tissues in a human body?

Answer 1

epithelium
connective
nervous
muscle

Question 2

describe epithelium

Answer 2

diverse structural arrangement depending on location and function of tissue

Question 3

what are the common functions of epithelial tissues?

Answer 3

lines all body surfaces
lines all tubes and cavities
-digestive system
-resp system
-cvs
barrier function
-boundary between different environments
-all substances entering and leaving body pass through epithelium

Question 4

what are the common structural features of epithelial tissues?

Answer 4

continuous sheets of cells
tightly bound together
polarised

Question 5

how does being tightly bound benefit?

Answer 5

protection against microbial invasion

provide opportunity to regulate movement of substances

Question 6

what are tight junctions?

Answer 6

create impermeable seal between adjacent cells

prevents water leakage

Question 7

what are desmosomes?

Answer 7

strong junctions
anchor adjacent cells together
ensure epithelial tissues can stretch and maintain contact

Question 8

what are 4 additional functions of epithelial tissues?

Answer 8

physical protection
-skin & oral cavity
diffusion of gases, nutrients and waste between blood & surrounding tissues
absorption of nutrients
-GIT
secretion
-sweat, mucus, enzymes,hormones

Question 9

how are epithelial tissues classed?

Answer 9

1. shape
2. number of cell layers
3. apical specialisations

Question 10

what are the 3 shapes of epithelial cells?

Answer 10

squamous
cuboidal
columnar

Question 11

what are the 2 numbers of layers?

Answer 11

simple-single layer

stratified- 2 or more layers

Question 12

what are the 3 apical specialisations?

Answer 12

microvilli
-increase apical SA
cilia
-movement of particulate matter
keratin
-strong protective apical layer

Question 13

describe simple columnar ciliated

Answer 13

function:

ciliary action facilitates transport of ovum from ovary to uterus

Question 14

describe pseudostratified columnar ciliated

Answer 14

function:

ciliary action propel surface layer mucus containing traooed particles towards pharynx

Question 15

what are goblet cells?

Answer 15

modified columnar epithelial cells
synthesise and secrete mucus
scattered throughout simple columnar epitheliums
resp/GIT

Question 16

describe stratified epithelia?

Answer 16

protection from mechanical abrasion
name shape at surface
cells mature from basal layer from continuously dividing stem cells
gradually migrate to surface and are shed as anucleate squames

Question 17

what is keratin?

Answer 17

enhances resistance to physical stress
epithelial cells accumulate keratin filaments as they mature
formation of tough, non-living surface layer
can be in stratified squamous epithelia

Question 18

what is transitional epithelium?

Answer 18

allows for expansion and stretch

only found in bladder

Question 19

describe stratified cuboidal

Answer 19

function:
secretory
location:
rare, some ducts and glands

Question 20

describe stratified columnar

Answer 20

function:
secretory and protective
location:
male urethra & lines some glands

Question 21

what is an ulceration?

Answer 21

break in continuity of epithelium

can be infections and non-infections

Question 22

what is oral squamous cell carcinoma?

Answer 22

dysplastic epithelial cells proliferate in an uncontrolled manner
destroy and incade adjacent tissues

Question 23

what is a carcinoma?

Answer 23

malignant tumour arising from epithelial tissue
subclassified by tissue of origin
squamous cell originates from stratified squamous epithelium