Cell Adhesion and the Extracellular Matrix Flashcards Preview

MD2001 > Cell Adhesion and the Extracellular Matrix > Flashcards

Flashcards in Cell Adhesion and the Extracellular Matrix Deck (14):
1

What is in the extracellular matrix?

+ Fibrillar proteins
- collagen
- elastin
- fibronectin
- laminin

+ Polysaccharides glycosaminoglycans (in proteoglycans)

2

What are GAGs?

Glycosaminoglycans: when organised by specific proteins they make proteoglycans

+ Long chains of repeating disaccharide units
+ Highly chahrged (-ve) and highly hydrated

3

What do fibroblasts synthesise?

+ Collagen
+ Elastin
+ Proteoglycans

4

Where is collagen synthesised and how is it released?

It is synthesised in the RER and assembled to form a triple helix (needs vitamin C)

It is released via the secretory pathway (through golgi, as procollagen)

5

What happens once procollagen has been secreted?

It is trimmed to tropocollagen and then cross-linked to make a fibril

6

What makes collagen secretion special?

Collagen is packaged into specialised (large) vesicles in the RER

7

What is the membrane tube surrounding fibroblasts called?

Fibropositor: these are oriented along the tendon direction in groups - collagen fibres

8

What do proteoglycans provide to the ECM?

+ Matrix support/cushioning/hydration
+ Glue-like function
+ Links between proteins of the ECM and ECM and cell surface

9

Name some different versions of GAG chains

+ Keratan sulfate (KS)
+ Chondroiton sulfate (CS)
+ Dermatan sulfate (DS)
+ Hearan sulfate (HS)

10

How does linking extracellular matrix to cytoskeleton work?

Collagen/proteoglycans bind Fibronectin that links to Integrins within the plasma memberane

Integrins themselves then bind via Adaptors to Actin cytoskeleton

11

What are the functions of myofibroblasts?

+ Fibroblast-like; secrete collagen

+ Smooth muscle-like; synthesis actin, myosin and desmin

12

What is the role of myofibroblasts in tissue damage?

+ Proliferate
+Secrete collagen (scaffold)
+ Consolidate damaged area (fibrous scar)
+ Contract (reduce size of damaged area; express focal adhesions and smooth muscle actin)

13

When are myofibroblasts also active, besides wound healing?

In tissue fibrosis e.g liver cirrhosis

14

What are the functions of adipocytes?

+ Insulation
+ Packing
+ Energy store