Epithelial cells

Question 1

What is epithelium?

Answer 1

A type of tissue which covers all of the exposed surfaces of the body, and protects, produces and secretes things

Question 2

What is tissue made up of?

Answer 2

cells, and an extracellular matrix

Question 3

What are the two different end of the cell called and where do they face?

Answer 3

An apical end = always faces the lumen (hollow area) or external surface

A basal end = faces inwards

Question 4

How does the cytoskeleton (specifically cilia and actin) work with epithelial cells?

Answer 4

Cilia exist inside of the epithelial cell and they stick to the membrane

Actin works on the peripheral of the cell for polarisation and non polarisation

Question 5

Where is epithelial tissue found?

Answer 5

On all internal and external surfaces of the body
such as fallopian tubes
oesophagus
blood vessels

Question 6

What is epithelium called in blood vessels?

Answer 6

Endothelium

Question 7

What is the function of epithelial tissue?

Answer 7

• protect our insides and tissues

- secrete and reabsorb

Question 8

What are the 5 main characteristics of epithelium?

Answer 8

1. There is very little space between each cell
2. Strong attachments between each cell
3. Cells are polarised/oriented
4. Epithelial tissue is avascular (no blood supply)
5. Epithelial cells sit on a basal laminar (basement membrane)

Question 9

what attachments connect epithelium on the lateral surface?

Answer 9

tight junctions
zonula adherencs
desmosone
gap junctions
infolding of membranes

Question 10

What attachments connect epithelium on the basal surface?

Answer 10

• hemidesmosone

Question 11

How are epithelium classified?

Answer 11

number of layers = simple or stratified

shape of the cell = squamous, cuboidal, columnar

Question 12

What are the different types of epithelium?

Answer 12

• simple squamous
• simple columnar
• stratified squamous
• keratinised stratified squamous
• transitional
• psuedostratified

Question 13

What is simple squamous epithelium + example?

Answer 13

epithilium which looks like fired eggs
- lines blood vessels
- has a central nucleus
eg =blood vessels

Question 14

What is simple columnar + example?

Answer 14

elongated epithelium cell with nucleus n the bottom 3rd of the cell
eg = small intestine

Question 15

What is stratified squamous + example?

Answer 15

multilayered squamous cells

eg = mouth, eosophogus, vagina

Question 16

What is keratinised stratified squamous + example?

Answer 16

squamous epithelium with keratin attachments

eg = dry skin/epidermis

Question 17

What is transitional epithelium + example?

Answer 17

stratified epithelium which changes shape depending on whether urine is in the bladder
eg = ONLY in urinary tract

Question 18

What is pseudostratified epithelium + example?

Answer 18

appears to be many layers thick but is actually only 1
does not sit on basement membrane
eg = trachea

Question 19

What is the difference between the dermis, epidermis and hypodermis?

Answer 19

epidermis = epithelium lining skin
dermis = dense irregular CN
hypodermis = area with large % adipose tissue

Question 20

What is the difference between villi, microvilli and cilia?

Answer 20

villi = small vascular projections that increase the SA of a membrane
microvilli = a microscopic projection of a tissue or cell
cilia = short microscopic vibrating structures that cause propulsion

Question 21

What are goblet cells? where are they found?

Answer 21

a column shaped cell in the respiratory/intestinal tract that secretes mucus

Question 22

Where are cilia found? examples

Answer 22

• oviduct - cilia move ovum/sperm into uterus

- trachea- mucos on epithelium traps debris and cilia beat it out of RT

Question 23

Provide examples of important roles the cytoskeleton plays in cells?

Answer 23

• maintains cell shape
• plays a role in cell division
• allows for the movement of organelles

Question 24

What are the 3 major components of the cytoskeleton?

Answer 24

• microtubules (tubulin)
• intermediate filaments (proteins such as keratin)
• microfilaments (actin)

Question 25

How does neutrophil chase bacteria?

Answer 25

the neutrophil advances a protruding structure at the leading edge of itself, and this is filled with newly polymerised actin filaments which undergo rapid cytoskeletal reogranisation for chase/movement

Question 26

what is the basal lamina/ basement membrane made up of?

Answer 26

collagen type 4, a glycoprotein called laminin and a proteoglycan called heparin sulfate

Question 27

what is the function of the basal lamina?

Answer 27

• cell adhesion
• cell orientation/shape
• binding to basal plasma membrane
• ensuring that epithelial cells do not pass the basal lamin (only cancer cells do)