L6 Epitheia

Question 1

what are the main functions of epithelial tissues?

Answer 1

protection
filtration
sensation
absorption
secretion

Question 2

what are the 3 types of structures the link cells to another and the basal lamina?

Answer 2

tight junctions
anchoring junctions
channel forming junctions

Question 3

describe tight junctions and there purpose

Answer 3

seal adjacent cells- prevents leaking between cells from bacteria and viruses. also prevent migration of membrane proetins- create cell polarity

Question 4

how are anchoring junctions categorised and what are the 2 main types?

Answer 4

they are categories by cytoskeletal filaments they interact with.
actin filament attachments or intermediate filament attachments

Question 5

describe actin filament attachments

Answer 5

Cell-cell= adherent junction

cell-basal lamina- focal adhesions

Question 6

describe intermediate filaments

Answer 6

cell-cell- desmosomes

cell-basal lamina- hemidesmosomes

Question 7

what is the basal lamina?

Answer 7

underlines all epithelia

strong flexible foundation a meshwork of different proteins

Question 8

what are the 4 proteins which the basal lamina is made up from?

Answer 8

lamina
type IV collagen
entactin
Perlacan

Question 9

what is the basement membrane

Answer 9

combination of the basal lamina and the reticular lamina (mainly composed of type III collagen)

Question 10

what are the 3 main function of the basement membrane

Answer 10

anchoring of epithelial cells to connect tissue .
mechanical barrier
important in angiogenesis

Question 11

describe gap junctions and there function?

Answer 11

form tiny intracellular channels

allow diffusion between cells. cell cell communication by movement of ions etc

Question 12

describe simple squamous epithelial tissue function/position

Answer 12

flat, one layer

absorption, filtration, minimal barrier for diffusion. found in capillaries alveoli and pleural cavities

Question 13

describe simple cuboidal function and position?

Answer 13

secretion/transportation

found in glands, ducts, and kidney tubules also cover ovaries

Question 14

describe the simple columnar tissue function and position?

Answer 14

function- absorption, protection,secretion

postion- digestive tract, may have microvilli to increase SA

Question 15

describer stratified squamous function and position

Answer 15

lost of layers of flat cells
provide protection can be keratinised in the top layer, will die if become too keratinised and then are shed!

found in the skin, mouth, upper throat and oesophagus

Question 16

Pseudo-stratified columnar

Answer 16

function- absorption and protection

postion- upper respiarotyr tract, trachea, where mucus is also have cilia to beat away mucus

Question 17

what are microvilli made from and what is there function

Answer 17

cytoskeletal protein network, massively increase surface area and absorption

Question 18

describe keratinised surfaces of skin?

Answer 18

skin is keratinised squamous epithelium
keratin provides an inert protective layer
as cell moves closet to the surface- karatohyalin granules produce keratin, cells become thinner. also begin to produce lipids for water proofing