Ground substance (water + protein + polysaccharides)

3 Main Functions of Connective Tissue

1. binds, support an strengthen

2. transport

3. fat storage

Epithelia differences and similarity

Differences: not found on surfaces, can be highly vascular (except for tendons)

Similarity: supplied by nerves (except cartilage)

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.

What does structure of ECM determine?

Connective tissue qualities

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.

Whole GAG complex (bottle brushes) do what?

Retain H2O

—> slippery

—> act as buffer

—> jelly like

Exopthalmos

• autoimmune over activation of the thyroid (Goitre)

• autoimmune action on fibroblasts in ECM of eye

• swelling of ECM + inc muscle size + increased fat

• deposition of GAGS + influx of H2O increase orbital content of eye

Where are the 3 protein fibres secreted from?

secreted by cells in the ECM/CT - often fibroblasts

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

Function: resist pulling forces

Features: strong, flexible, features vary based on location, parallel bundles

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

Marfan’s

• body produces TGFb - increases growth - does not bind normally to fibrillin to keep it inactive

• individuals usually tall, long limbed, chest deformity and normal life span but need medical vigilance

• weakened heart valves + arterial walls —> can be life threatening