Physiology of joints

Question 1

What are the three main types of joint?

Answer 1

Synovial
firbous
cartilaginous

Question 2

What type of joints can be found in the skull?

Answer 2

Fibrous

Question 3

What are examples of cartilaginous joints?

Answer 3

Intervertebral discs, pubic symphysis, part of the sacroiliac joints, costochondral joints

Question 4

What is the synovial membrane?

Answer 4

Vascular connective tissue with capillary network and lymphatics

Question 5

What produces synovial fluid?

Answer 5

Synovial cells ( fibroblasts)

Question 6

What are the articular surfaces of the bones covered with?

Answer 6

Cartilage

Question 7

define simple synovial joint

Answer 7

one pair of articular surfaces

Question 8

Define compound synovial joint

Answer 8

more than one pair of articular surfaces

Question 9

What is the role of joints during purposeful movement?

Answer 9

Stress distribution

confer stability

Question 10

What 3 things are important in conferring stability during purposeful movement?

Answer 10

Shape of the articular component
ligaments
synovial fluid acts as an adhesive seal that freely permits sliding motion between articular surfaces

Question 11

What is joint lubrication provided by (3)

Answer 11

Cartilage interstitial fluid
synovial- derived HYALURONIC ACID (mucin)- a polymer of disaccharie
Synovium-derived LUBRICIN-a glycoprotein

Question 12

Aside from lubrication ect what does synovial fluid do? (2)

Answer 12

Aids in the nutrition of articular cartilage

supplies the chondrocytes wth )2 and nutrients and remove CO2 and waste products

Question 13

Why does the synovial fluid have a high viscosity?

Answer 13

presence of hyaluronic acid

Question 14

What does the viscosity and elasticity of the synovial fluid vary with?

Answer 14

joint movement

Question 15

What are the other constituents of the synovial fluid derived by?

Answer 15

dialysis of blood plasma

Question 16

The synovial fluid is a static pool T/F

Answer 16

False- the synovial fluid is constantly replenished and absorbed by the synovial membrane

Question 17

What is rapid movements of joints associated with?

Answer 17

decreased viscosity

increased elasticity

Question 18

What colour is the synovial fluid normally? Does this ever change?

Answer 18

Normally - high viscosity, colourless and transparent
Inflammatory- Low viscosity, yellow, translucent
Septic- variable viscosity and colour, opaque
in synovial tap and in haemorrhage arthritis it turns red

Question 19

What distributes contact pressure to subchondral bone?

Answer 19

Articular cartilage

Question 20

What plays a significant role in determining the mechanical properties of cartilage?

Answer 20

The composition of the cartilage ECM and the interaction between the liquid and solid phase

Question 21

What is the structure of articular cartilage?

Answer 21

Superficial zone - 10-20%
Middle zone- 40-60%
Deep zone - 30%
Calcified zone

Question 22

What do the zones differ in

Answer 22

organisation of collagen fibres

relative content of cartilage components

Question 23

The articular cartilage is usually ____. it is _____ and has a ___ -__ property

Answer 23

hyaline
elastic
sponge-like

Question 24

What is the ECM predominantly consist of?

Answer 24

water (70%)-content dec w age
collagen( 20%)-mainly type 11,dec w age
Proteoglycans (10%)

Question 25

What is the purpose of water in the cartilage?

Answer 25

Maintain the resiliency of the tissue and contribute to the nutrition and lubrication system

Question 26

What is the purpose of collagen in the cartilage?

Answer 26

Provide tensile stiffness and strength

Question 27

What is the purpose of proteoglycan in the cartilage?

Answer 27

Compressive properties associated with load bearing

Question 28

What is the ECM(which makes up 98% of total cartilage volume) synthesised, organised,degraded and maintained by?

Answer 28

Chondrocytes ( makes up the other 2%)

Question 29

The articular cartilage is ______. Therefore chondrocytes receive nutrients and o2 via the _____ ____

Answer 29

avascular

synovial fluid

Question 30

What breaks down ECM?

Answer 30

metalloproteinase proteolytic enzymes e.g. collagenase and stromelysin

Question 31

When could joint disease occur?

Answer 31

Rate of ECM degradation exceeds the rate of synthesis

Question 32

What is the catabolic factors of cartilage matrix turnover?

Answer 32

Stimulates proteolytic enzymes and inhibit proteoglycan synthesis

• TNF a
• IL 1

Question 33

What are the anabolic factors in cartilage matrix turnover?

Answer 33

Stiualate proteoglycan synthesis and counteract effects of IL 1

• TGF B
• IGF 1

Question 34

What are markers of cartilage degradation?

Answer 34

• Serum and synovial keratin sulphate
• -inc levels indicate breakdown, age and osteoarthitiris
• Type II collagen insynovial fluid
• -inc levels indicate breakdown

Question 35

What does repeated wear and tear in a joint give rise to?

Answer 35

osteoarthritis

Question 36

Synovial cell proliferation and inflammation cause

Answer 36

rheumatoid arthritis

Question 37

Deposition of salt crystals e.g. uric acid gives rise to

Answer 37

gouty arthritis

Question 38

Injury and inflammation to periarticular structures causes…

Answer 38

soft tissue rheumatism