Joints, Synovial Fluid and Cartilage

Question 1

What are the different structural classifications of joints?

Answer 1

1 - Fibrous

2 - Cartilaginous

3 - Synovial

Question 2

What are the distinguishing features of each of the joint types?

Answer 2

Fibrous - very strong joints with little movement

Cartilaginous - Layers of cartilage instead of fibrous tissue

Synovial - The most complex type of joints and also the joints that can perform the most movement

Question 3

Where in the body can fibrous joint types be found?

Answer 3

1 - Cranial sutures

2 - Peridontal ligament (between tooth and collagen fibres)

3 - Interosseus membranes (stops radial & ulnar bones being pulled apart)

Question 4

Where in the body can cartilaginous joints be found?

Answer 4

1 - Growth plates of long bones

2 - Vertebral discs & their vertebral bodies

Question 5

What is the difference between primary cartilaginous and secondary cartilaginous joints?

Answer 5

Primary - Only Hyaline cartilage

Secondary - Hyaline cartilage & Fibrocartilage

Question 6

Where in the body can synovial joints be found?

Answer 6

1 - Knees & Elbows (Hinge)

2- Vertebral column facet joints (Plane)

3 - Shoulder (Ball & Socket)

4 - Radio-Ulnar (Pivot)

5 - Thumb (Saddle)

6 - Atlanto-axial joint (Condylar)

Question 7

What are the components of synovial joints?

Answer 7

1 - Articular discs

2 - Ligaments

3 - Bursae

Question 8

What is the structure & function of hyaline cartilage?

Answer 8

Structure:

• Superficial layer: Flattened chondrocytes which produce collagen and glycoproteins (lubricin)
• Transitional layer: Round chondrocytes which produce proteoglycans such as aggrecan
• >75% water

Function:

• Due to high water content, hyaline cartilage is very good at cushioning joints
• Horizontally oriented fibres of superficial layer increases the strength of the joint

Question 9

What are the important molecules found within joints?

Answer 9

Glycoproteins - Proteins to which oligosaccharides are attached, e.g. Lubricin

Proteoglycans - Proteins which are heavily glycosylated, e.g. Aggrecan

Glycosaminoglycans - Long, unbranched polysaccharides, e.g. Hyaluronic acid

Question 10

What are the main components of synovial fluid?

Answer 10

1 - Hyaluronic acid

2 - Lubricin

3 - Fluid component from blood plasma

Question 11

What is the function of synovial fluid?

Answer 11

1 - Nutrition of cartilage

2 - Removal of waste products

3 - Lubrication of joints