Epithelial Cells

Question 1

Define nuclear lamina

Answer 1

specialised cytoskeleton on internal surface of nuclear envelope, important in stabilising nuclear envelope in cell division

Question 2

define peroxisome

Answer 2

single membrane that contains enzymes and is involved in lipid and aerobic metabolism oxidation reactions

Question 3

What are microtubules made up of?

Answer 3

alpha and beta tubulin heterdimers that are 20nm thick

Question 4

What are microtubules involves in?

Answer 4

cell shape, track for organelle movement and cytoplasmic components, major component of cilia and flagellae

Question 5

What are intermediate filaments?

Answer 5

filament proteins that form rope like filaments 10-15nm in diameter

Question 6

What are the types of intermediate filaments? Where are they found?

Answer 6

cytokeratins - epithelial
vimentin - mesenchymal
neirofilament - neurones
design - muscle

Question 7

Whats is the function of intermediate filaments?

Answer 7

give mechanical strength and connects desmosome cell-cell adhesions

Question 8

What are microfilaments?

Answer 8

polymers of actin that are associated with adhesion belts (in epithelial and endothelial cells) and other plasma membrane proteins, 5-9nm diameter

Question 9

What are microfilaments involved in?

Answer 9

cell same and movement, accessory proteins act with actin to control movement and actin organisation

Question 10

What are the types of microfilaments?

Answer 10

monomer = globular action = G-actin
microfilament = filament action = F-actin

Question 11

Name the cell types of give examples

Answer 11

connective tissue - fibroblasts, osteocytes, chondrocytes
contractile tissue - skeletal/cardiac/smooth muscle
haematopoietic - blood cells, bone marrow
neural - neurones, glial
epithelial

Question 12

Define tissues

Answer 12

group of cells whose type, architecture and organisation are integral to function

Question 13

What is an EC matrix?

Answer 13

tissue deposited by cells to form insoluble envorinement, that is composed of fibrillar proteins embedded in hydration gel

Question 14

How are epithelial cells organised?

Answer 14

stable cell-cell junctions to form continuous cohesive layer

line internal/external surfaces

Question 15

Where are cell-cell junctions found?

Answer 15

apical region of cell-cell contact as junctional complex

Question 16

What are the 2 forms of cell-cell junctions

Answer 16

zonulae/belts

maculae/spots

Question 17

How are cell-cell junctions typically arranged?

Answer 17

an apical junctional complex contains tight junction near apex, then adhesion belt, then desmosomes/spot adhering junctions throughout lateral membrane

Question 18

What is the arrangement of a tight/belt junction?

Answer 18

points on adjacent membranes form close contacts at apical lateral membrane, highly elaborate networks contacts create tight seal for paracellular pathways

Question 19

Function of tight/belt junction?

Answer 19

segregates atypical and basolateral membrane polarity

Question 20

What is the arrangement of an adhesion belt?

Answer 20

formes basal to the apical tight junction, adhesion molecule is cadherin which associates with microfilament cytoskeleton

Question 21

Function of adhesion belt?

Answer 21

controls assembly of the other junctions

Question 22

What is the arrangement of the the spot junction/desmosomes?

Answer 22

found at multiple spots between adjacent cell membranes with a cadherin-Like adhesion molecule
linked to intermediate filament

Question 23

Function of spot junction

Answer 23

provides mechanical continuity between cells

Question 24

What is the arrangement of a gap junction?

Answer 24

clusters of pores that are continuous with pores in adjacent cell membrane

Question 25

Function of gap junction?

Answer 25

allow passage of ions and small molecules between cells, electrical signal passage

Question 26

Name the cell types and the cancer they cause

Answer 26

connective tissue = sarcoma
contractile tissue = sarcoma
haematopoietic = leukaemia and lymphoma
neural = neuroblastoma and glioma
epithelial = carcinoma