Epithelium Tissue

Question 1

what are they?

Answer 1

cells which cover/sperate/isolate and protects parts inside and outside the body and surfaces

Question 2

characteristics (5)

Answer 2

1. Layers of cells (Cellular w. little extra cellular matrix)
2. cover surfaces & form glands
3. bind to adjacent cells via matrix connections (‘special structures’)
4. non-vascular: no penertrating BVs, so nurients diffuse from nearby capillaries
5. cells divide & replace via mitosis

Question 3

Functions (5)

Answer 3

1. Protect structures they surround
2. Act as a barrier to substances
3. Allow substance movement & exchange
4. Secrete substances (glands)
5. Allow the absorption of substances (e.g. nurients)

Question 4

how are they classified (2)

Answer 4

by shape & number of layers

Question 5

number of layers classifications (3)

Answer 5

1. Simple
2. Stratified
3. Pseudo-stratified

Question 6

Shape classifications (3)

Answer 6

1. Squamous
2. Cuboidal
3. Columar

Question 7

Types (8)

Answer 7

1. Simple Squamous
2. Simple Cuboidal
3. Simple Columar
4. Stratified Squamous
5. Stratified Cuboidal
6. Stratfied Columar
7. Pseudo-stratfied columnar
8. Transitional

Question 8

simple squamous

Answer 8

Appearence: single layer, flat & hexagonal
Functions: diffusion, filtration, secretion, protect against fiction

Question 9

simple cuboidal

Answer 9

Appearence: single layer, cube shaped cells, some have villi/cilla
Functions: secrete & absorb ions, move embedded particles

Question 10

simple columar

Answer 10

appearence: single layer, narrow & tall cells, some have micro-villi/cilla
functions: ciliated cells move particles, secrete in glands & small intestine, absorbtion

Question 11

stratified squamous

Answer 11

appearence: muli-layered, basal layer cuboidal and gets progressively flatter cells as you go up, keterainsed & non-ketarised
functions: protect against abrasion, barrier to infection

Question 12

stratified cuboidal

Answer 12

appearence: muli-layered, ‘some-what’ cuboid shaped
functions: secretion, absorbtion, protection against infection

Question 13

stratified columar

Answer 13

appearence: multi-layered, tall & narrow cells
functions: cilliated in larynx to remove debris, protection, secretion

Question 14

pseudostratified columnar

Answer 14

appearence: single layer, mixture of cell shapes, some can reach entire length of tissue, nuclei found at different levels, almost always ciliated
associated cells: goblet cells
function: synthesise & secrete mucus, move mucus/fluid w. forgein particles over the surface

Question 15

transitional

Answer 15

can be non-stretched (stratified cubes) or stretched (squamous and less layers) depending on fluid presence (streched w. fluid)
function: accomodate fluid, protect against caustic effects of urine