Epithelial cells

Question 1

What are the three constituents of the Cytoskeleton?

Answer 1

Microtubules
Intermediate filaments
Microfilaments

Question 2

How thick are microtubules?

Answer 2

20nm

Question 3

What are four functions of microtubules?

Answer 3

Maintain cell shape
Act as tracks for movement of cellular components
Major component of Cillia/Flagella
Form mitotic spindles

Question 4

What is the arrangement of microtubules in cillia?

Answer 4

9+2

9 microtubule doublets and 2 central microtubules

Question 5

What is the diameter of intermediate filaments?

Answer 5

10-15nm

Question 6

What do intermediate filaments do?

Answer 6

Give cell mechanical strength

Involved in desmosome cell-cell adhesion

Question 7

What is the diameter of microfilaments?

Answer 7

5-9nm

Question 8

What are microfilaments made out of?

Answer 8

Globular actin polymer

Question 9

What are microfilaments involved in?

Answer 9

Cell shape and movement

Question 10

How many cells are there in an average human body?

Answer 10

37 trillion

Question 11

How many types of cell types are there?

Answer 11

~200

Question 12

What are the five main cell groups?

Answer 12

Connective tissue
Contractile tissue
Haematopoietic cells
Neural cells
Epithelial cells

Question 13

What types of tumour originate from these cell types:
Mesenchymal (connective/muscle)
Haematopoietic
Neural
Epithelial

Answer 13

Mesenchymal (connective/muscle): Sarcomas

Haematopoietic: Leukaemias, lymphomas

Neural: neuroblastomas, gliomas

Epithelial: carcinomas

Question 14

What is the extracellular matrix?

Answer 14

Matrix deposited by cells and forms insoluble extracellular environment, composed of fibrillar proteins in hydrated gel, and organisation depends on location

Question 15

Name the five types of Cell-Cell junction

Answer 15

Tight Junction
Adherans Junction
Desmosome
Gap Junction
Hemidesmosome

Question 16

How are Cell-Cell junctions typically arranged?

Answer 16

In apical junction complex in epithelia
Zonulae (belts)
Maculae (spots)

Question 17

What us the Tight junction?

Answer 17

“belt junction” sealing strands of occludin form a network of contacts, acts to seal paracellular pathways and segregate apical/basolateral membrane polarity

Question 18

What is the adhesion belt?

Answer 18

“belt junction”; transmembrane cadherin molecules associate with each other and to the actin cytoskeleton of their cell to join the bundles in one cell to the next; controls assembly of other junctions

Question 19

What are desmosomes?

Answer 19

“spot junction”; cadherin-like molecules join the intermediate (keratin) filament cytoskeleton at spots; provides good mechanical continuity between cells

Question 20

What is the gap junction?

Answer 20

“spot junction”; continuous pores between membranes - affected by pH, [Ca2+] and voltage so can open and close to control communication; allow passage of ions and small molecules between cells

Question 21

What are hemidesmosomes?

Answer 21

“spot junction” join the cell to the basal lamina

Question 22

Whats the acronym for remembering all the C-C junctions?

Answer 22

TADGH

That arsehole don’t get hate!