Ground substance (water + protein + polysaccharides)

Glycosaminoglycans (GAGS)

Sugars that join with core proteins to form proteoglycans.

What are the features of glycosaminoglycans (GAGS)?

GAGS can be either sulphated or non-sulphated.

Sulphated GAGS examples

Dermatan sulphate, Heparin sulphate, Keratan sulphate, Chondroitin sulphate.

Non-sulphated GAG example

Hyaluronic acid, which does not bind directly to a protein backbone but connects to several proteoglycans.

What is the significance of GAGS being highly polar?

They attract water, making the ground substance more jelly-like.

Hyaluronic acid - Functions (4)

Provides a viscous slippery surface, binds cells together, lubricates joints, and maintains the shape of the eyeball.

Hyaluronidase - Produced by and function

Produced by white blood cells, sperm and some bacteria; makes the ground substance more liquidy to facilitate movement or access to the egg.

Function(2) of Chondroitin sulphate

Supports and provides adhesive features of cartilage, bone, skin, and blood vessels.

Where is Keratan sulphate found? (3)

In bone, cartilage, and the cornea of the eye.

Dermatan sulphate locations (4)

Found in skin, tendons, blood vessels, and heart valves.

Abnormal ECM ground substance symptoms

Exophthalmos, commonly seen in younger women, associated with autoimmune overreaction affecting fibroblasts.

What is Goitre?

Swollen thyroid due to autoimmune action, leading to the deposition of GAGS and increased water influx in the orbital contents.

Collagen fibres - Functions, features (3), location (4)

Function: resist pulling forces

Features: strong, flexible, features vary based on location

Location: bone, cartilages, tendons and ligaments 

Reticular fibres - Functions (3 and where), Features (3)

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 and branching - spreads through tissue

Elastic fibres - Function, Location(3), Features(3)

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 

Function: elasticity and resilience