Histology Of Epithelial Cells

Question 1

What are epithelial cells?

Answer 1

They line parts of the body that comes into contact with an external environment

Question 2

What are endothelial cells?

Answer 2

A specialised type of epithelial cell, specialised molecularly and physically to coordinate blood homeostasis

Question 3

What is the 4 functions of epithelial cells?

Answer 3

Protection- preventing unregulated movement of microbes

Absorption- transport substances we need from external environment

Lubrication- epithelial cells secrete mucus = minimise the sheer stress

Movement- cilia act like a conveyer belt which move foreign particles and microbes away from the lungs

Question 4

What is the underlying layer of proteins and glycoproteins called?

Answer 4

Basement membrane

Question 5

What two ways can passage occur?

Answer 5

• paracellular
• transcellular

Question 6

What are tight junctions?

Answer 6

Proteins that stick epithelial cells together in their lateral membranes

Question 7

What do tight junctions control?

Answer 7

The passage of substances between cells

They are a complex mixture of proteins, the assembly of which is very tightly regulated

Question 8

What are gap junctions?

Answer 8

Trafficking of substances between cells

Question 9

What does it mean when epithelial cells are polar?

Answer 9

They have distinctly different surfaces with specialised roles

Question 10

What are pseudostratisfied epithelial cells?

Answer 10

False layered

Question 11

What are transitional epithelial cells?

Answer 11

Changeable / dynamic

Question 12

Where is simple squamous epithelial present?

Answer 12

In areas where easy transmembrane movement is advantageous

The aveoli- gas exchange

Bowman’s capsule- support rapid diffusion in kidney

Question 13

Simple squamous epithelial does not provide…

Answer 13

Much protection from mechanical abrasion

Question 14

What is the function of simple cuboidal epithelial cells?

Answer 14

Capable of fulfilling complex roles eg-secretion

Found in glands which specialise in secretion including salivary glands

Question 15

Where are simple columnar cells found?

Answer 15

Capable of secreting large amount of substances, so they are found in areas where lubrication is required, such as throughout the intestines

Question 16

What are striated squamous like?

Answer 16

Flat and scale-like

Found in surfaces that are subject to high levels of mechanical abrasion

Question 17

What are the two varieties of striated squamous?

Answer 17

Wet (non-keratinising)

Dry (keratinising)

Question 18

Describe keratinising striated squamous epithelium;

Answer 18

Produce a tough protein - keratin

Top layer is dead

This produces a dry surface, which protects underlying delicate tissues from external forces eg-skin

Question 19

Describe non-keratinising striated squamous epithelium;

Answer 19

Occur in wet/moist environments where abrasion is likely

Top layer is alive

Produced a moist surface, protects underlying delicate tissues from external forces eg-inside mouth/osephagus

Question 20

What does the presence of misaligned nuclei give?

Answer 20

The impression it is stratisofed but is it not

Question 21

Why does the transitional epithelium change shape?

Answer 21

allows the organ/tube to increase in size and shrink

Question 22

How much cilia is in a ciliated cell?

Answer 22

Over 200

Question 23

Where is ciliation most commonly found?

Answer 23

On columnar epithelial cells

In respirory tract where they move mucus laden with dust/microbes away from the lungs

Question 24

What are microvilli?

Answer 24

Finger like prostusions on the surface

Main role of absorption

Do not move

Increase surface area for absorption of nutrients from the gut lumen

Question 25

What is the function of goblet cells?

Answer 25

Synthesise & secrete mucus

Modified columnar epithelial cells