Ground substance (water + protein + polysaccharides)

Composed of 

1. Water

2. Proteins

3. Polysaccharides

Sugars: glycosaminoglycans (GAGS) → join with core proteins to form proteoglycans 

Features of GAGS

GAGS can either be sulphated or non-sulphated 

Sulphated 

→ Dermatan sulphate

→ Heparin sulphate

→ Keratan sulphate 

→ Chondroitin sulphate 

Non-sulphated

→ Hyaluronic acid - does not bind directly to protein backbone but is joined to several proteoglycans 

GAGS = highly polar 

• Attract H2O so trap water to make ground substance more jelly like 

Applications of GAGS 

Hyaluronic acid - viscous slippery surface, binds cells together, lubricates joints and maintains shape of eyeball 

Hyaluronidase 

• Produced by white blood cells, sperm and some bacteria 

• Makes ground substance more liquidy so can move more easily in it or makes access to the egg easier for the sperm 

Chondroitin sulphate

• Support and provide adhesive features of cartilage, bone, skin and blood vessels

Ketanan sulphate

• Found in bone, cartilage, cornea of the eye 

Dermatan sulphate 

• Found in skin, tendons, vlood vessels, heart valves 

Sometimes can get abnormal ECM ground surface (OLM girl)

→ Exophthalmos 

→ most common younger women 

→ Gorture (swollen thyroid) 

→ autoimmune overreaction 

→ autoimmune action on fibroblasts in ECM of eye

→ deposition of glycosaminoglycans and influx of H2O increase orbital contents

Collagen fibres 

Function: resist pulling forces

Features: strong, flexible, features vary based on location

Location: bone, cartilages, tendons and ligaments 

Reticular fibres

Functions: strength and support + form part of basement membrane + forms networks in vessels and through tissues (adipose tissue, nerve fibres, smooth muscle tissues) : 

Features: Collagen with coating of glycoprotein, made by fibroblasts, thinner, branching - spreads through tissue

Elastic fibres 

Features: thinner than collagen + fibrous network + elastin surrounded by fibrillin to give more strength and stability + can be stretched to 150% 

Location: in skin, blood vessels and lung