Types of epithelium

Question 1

What is an epithelium

Answer 1

cohesive cells resting on basement membrane determined by shape, number of layers and specialized surface

Question 2

what are the 3 shapes of an epithelium cell

Answer 2

squamous
columnar
cuboidal

Question 3

describe the nucleus appearance of the epithelial cells

Answer 3

squamous- elongated flat nucleus parallel to basement membrane
cuboidal- rounded nucleus
columnar- elongated nucleus, perpendicular to basement membrane

Question 4

what are the types of specialized surfaces and function for each one

Answer 4

cilia- movement of particles
keratin- protection
microvilli- increases surface area for absorption

Question 5

list the common function and an example of where they are found of each:
1)Simple squamous epithelium
2)Simple cuboidal epithelium
3)SImple columnar epithelium
4)Stratified squamous
5) stratified columnar epithelium

Answer 5

1)Simple squamous epithelium: For short diffusion distance such as alveoli/ endothelial lining

2)Simple cuboidal epithelium: secretion of substances such as in small ducts, glands and thyroid follicles

3)Simple columnar epithelium: mostly in absorvative layers such as stomach and intestine lining

4)Stratified squamous: lining of outer surfaces providing protection such as skin, oesophagus, vagina and anus

5)Stratified columnar epithelium: for large ducts such as salivary glands, urethra and epiglottis

Question 6

what makes the urinary epithelium special

Answer 6

It is a transitional epithelium “urothelium”
-Type of epithelium where surface cells change shape according to the bladder’s stretch
-Outermost layer changes from cuboidal when relaxed to squamous when stretched

Question 7

What type of special junction is present in the urinary epithelium to allows it to withstand high toxicity

Answer 7

Tight junctions

Question 8

What is they type of layer in the respiratory track

Answer 8

Pseudo stratified columnar ciliated epithelium with goblet cells

Question 9

Why is it pseudo stratified

Answer 9

All cells rest on the same basement membrane making it 1 layer but “pseudo” (false) as the nuclei of the cells are not on the same level

Question 10

List the type of cell junctions and their function

Answer 10

1) tight junctions: creates a water tight seal

2) adherens junction: provides strong mechanical attatchment with actin filaments

3)desmosomes: holds cells tightly by attatching to keratin intermediate filaments. can be moved by cell signalling to stretch and move upwards

4) hemi-desmosomes: attaches lowemost epithelium cells to basement membrane

5) gap-junction: Provides a gate channel for cells to transport ions and water (بوابه)