Joints

Question 1

What are the 3 major types of joitns?

Answer 1

Fibrous
Cartilaginous
Synovial

Question 2

Subtypes of Cartilaginous joint?

Answer 2

Primary = Hyaline cartilage only
Secondary = Hyaline & Fibrocartilage

Question 3

What is a fibrous joint + some examples?

Answer 3

Fibrous connective tissue between 2 bones, specifically collagen.

Periodontal ligament, cranial sutures & interosseous membranes

Question 4

Describe the structure of a synovial joint?

Answer 4

Synovial cavity filled with fluid encased in a synovial membrane.
All inside a fibrous capsule with articular cartilage on the outside

Question 5

What are the 6 types of synovial joint?

Answer 5

Hinge - Knee
Pivot - Atlas & Axis
Ball & Socket - Shoulder
Saddle - Thumb
Condylar - Atlas & Skull
Plane - vertebral facets

Question 6

Describe the vasculature, lymphatic drainage and nerves supply of a cartilage?

Answer 6

Avascular
Alymphatic
Aneural

Hence why synovial fluid is required to remove waste/supply articular cartilage in synovial joints

Question 7

What do we call the synovial membrane and what does it do?

Answer 7

The synovium
Produces synovial fluid and drains it through the capillaries

Question 8

What are the types of synoviocytes

Answer 8

Type A - resemble macrophages & remove debris (somewhat contribute to fluid)

Type B - Resemble fibroblasts and primarily produce synovial fluid

Question 9

What makes up synovial fluid?

Answer 9

1) Hyaluronic Acid
2) Lubricin
3) Fluid component comes from plasma

Question 10

Functions of synovial fluid?

Answer 10

Provide Nutrition to cartilage
Drain waste
Lubrication

Question 11

Name 3 types of lubrication?

Answer 11

Boundary
Hydrodynamic
Weeping

Question 12

Describe boundary lubrication?

Answer 12

Glycoproteins e.g. lubricin bind to receptors on the articular surface to form a thin film

Question 13

Describe hydrodynamic lubrication?

Answer 13

Liquid pressure keeps surfaces apart
The viscosity of the fluid changes with load and velocity on the joint

Question 14

Describe weeping lubrication?

Answer 14

High load causes the fluid in the cartilage to be squeezed into the synovial cavity

Question 15

What 3 factors affect joint stability?

Answer 15

• Shape of articulating surface
• Capsule & Ligament strength
• Muscles e.g. the rotator cuff muscles on your shoulder

Question 16

Describe the layers within hyaline cartilage?

Answer 16

The superficial or Tangential layer is near the articular surface and made of flattened chondrocytes that produce collagen and glycoproteins e.g. lubricin

The transitional Layer is below this & made up of round chondrocytes that produce proteoglycans like aggrecan

Question 17

How does collagen orientation change within hyaline cartilage?

Answer 17

Its side to side in the superficial layer to deal with shearing forces at the surface

And vertical at the transitional layer to deal with compression

Question 18

Whats the difference between glycoproteins and proteoglycans?

Answer 18

Glycoproteinsare mostly protein e.g. lubricin

Proteoglycans are mostly carb e.g. aggrecan