Physiology of Joints - 04/10/18

Question 1

What are the three types of joints?

Answer 1

Synovial
Fibrous
Cartilaginous

Question 2

What is another name for fibrous joints?

Answer 2

Synarthrosis

Question 3

What are fibrous joints?

Answer 3

Bones united by fibrous tissue

Question 4

Do fibrous joints allow movement?

Answer 4

No`

Question 5

What is an example of a fibrous joint?

Answer 5

Skull sutures

Question 6

What is another name for cartilaginous joints?

Answer 6

Amphiarthrosis

Question 7

Do cartilaginous joints allow movement?

Answer 7

Yes but limited

Question 8

What are some examples of cartilaginous joints?

Answer 8

Intervertebral discs
Pubic symphisis
Part of sacroiliac joints
Costochondral joints

Question 9

What is another name for synovial joints?

Answer 9

Diarthrosis

Question 10

What are synovial joints?

Answer 10

Bones separated by a cavity and united by a fibrous capsule

Question 11

What is in a synovial joint?

Answer 11

Synovial fluid

Question 12

What is the inner aspect of the fibrous capsule lined with in synovial joints?

Answer 12

Synovial membrane

Question 13

What is the synovial membrane made of?

Answer 13

Vascular connective tissue

Question 14

What type of cell are present in the synovial membrane?

Answer 14

Synovial cells aka Fibroblasts

Question 15

What produces the synovial fluid?

Answer 15

Synovial cells

Question 16

What covers the articular surfaces of bone?

Answer 16

Cartilage

Question 17

What are the two types of synovial joints?

Answer 17

Simple

Compound

Question 18

What is a simple synovial joint and what is an example?

Answer 18

One pair of articular surfaces

Question 19

What is a compound synovial joint and what is an example?

Answer 19

More than one pair of articular surfaces

Question 20

How are joints supported?

Answer 20

Extra-articular surfaces

Question 21

What are 3 extra articular surfaces?

Answer 21

Bursa
Tendon
Ligament

Question 22

What are the two physiological functions of joints?

Answer 22

Structural support

Purposeful motion

Question 23

What are the 3 roles of joints during purposeful motion?

Answer 23

Stress distribution
Confer stability
-Shape of the articular component
-Ligaments
-Synovial fluid 
Joint lubrication

Question 24

What provides joint lubrication?

Answer 24

Cartilage interstitial fluid
Synovium derived hyaluronic acid (mucin)
Synovium derived lubrcin

Question 25

What are the 5 functions of synovial fluid?

Answer 25

``` Lubricates Joint Facilitates joint movements Helps minimize wear and tear Aids in nutrition of articular cartilage Supplies the chondrocytes (cartilage cells) with O2 and nutrients and removes CO2 and waste products ```

Question 26

Is the synovial fluid a static poole?

Answer 26

No | It is constantly replenished and absorbed

Question 27

Is synovial fluid viscous and why?

Answer 27

Yes | Mainly due to the presence of hyaluronic acid (mucin) produced by synovial cells

Question 28

What are some other components of synovial fluid and how are they derived?

Answer 28

Uric acid | By dialysis of blood vessels

Question 29

Are there lots of cells in the synovial fluid?

Answer 29

Usually very little

Question 30

What does rapid movement do to the synovial fluid?

Answer 30

Decreases viscosity | Increases elasticity

Question 31

What is an example of a condition where the synovial fluid becomes defective?

Answer 31

Osteoarthritis

Question 32

What does normal synovial fluid look like/

Answer 32

Clear and colourless

Question 33

How many WBCs are in synovial fluid?

Answer 33

<200WBC/mm3

Question 34

When does the WBC count increase in the synovial fluid?

Answer 34

Inflammatory and septic arthritis

Question 35

When does the synovial fluid turn red?

Answer 35

Traumatic synovial tap | Haemorrhagic arthritis

Question 36

What colour is inflammatory synovial fluid?

Answer 36

Yellow

Question 37

What are the two functions of articular cartilage?

Answer 37

Prevents wear and tear | Distributes contact pressure to subchondral bone

Question 38

What determines the mechanical properties of cartilage?

Answer 38

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

Question 39

From superior to inferior, name the structure of articular cartilage?

Answer 39

``` Articular surface Superficial zone Middle zone Deep zone Calcified zone Subchondral bone ```

Question 40

How are the zones of articular cartilage differ?

Answer 40

Organization of collagen fibres and relative content of cartilage components

Question 41

What type of cartilage is articular cartilage?

Answer 41

Hyaline

Question 42

What are the properties of articular cartilage?

Answer 42

Elastic | Sponge-like

Question 43

Where does articular cartilage cover?

Answer 43

Articular surfaces of bones

Question 44

What is the ECM made up of?

Answer 44

70% Water 20% Type 2 collagen 10% Proteoglycans

Question 45

What accounts for 70% of the cartilage wet weight?

Answer 45

Water

Question 46

Where is 80% of cartilage water distributed?

Answer 46

Near the articular surface

Question 47

What happens to cartilage water content with age?

Answer 47

It decreases

Question 48

What does the water in cartilage allow?

Answer 48

Maintains resiliency of the tissue and contributes to the nutrition and lubrication system

Question 49

What accounts for 20% of the cartilage wet weight?

Answer 49

Collagen

Question 50

What type of collagen is present in cartilage?

Answer 50

Type 2

Question 51

What in the function of the collagen in the cartilage?

Answer 51

Maintains cartilage architecture | Provides tensile stiffness and strength

Question 52

What accounts for 10% of cartilage wet weight?

Answer 52

Proteoglycan

Question 53

Where is the highest concentration of proteoglycan found?

Answer 53

Middle and deep zone

Question 54

What is proteoglycan composed of?

Answer 54

Mainly glycosaminoglycan

Question 55

What is proteoglycan responsible for?

Answer 55

Compressive properties associated with load bearing

Question 56

What makes up >98% of cartilage volume?

Answer 56

ECM

Question 57

What synthesizes, organizes, degrades and maintains the ECM?

Answer 57

Chondrocytes

Question 58

Is the articular cartilage vascular or avascular?

Answer 58

Avascular

Question 59

What happens when there are changes in the amounts of each cartilage component?

Answer 59

It would change the mechanical properties of cartilage

Question 60

What would happen if the rate of ECM degradation happened faster than the rate of its synthesis?

Answer 60

Joint disease

Question 61

What are the catabolic factors of cartilage matrix turnover?

Answer 61

Stimulate proteolytic enzymes and inhibits proteoglycan synthesis E.g. TNFa, IL-1

Question 62

What are the anabolic factors of the cartilage matrix turnover?

Answer 62

Stimulates proteoglycan syntheis and counteracts the effects of IL-1 E.g. TGF, IGF-1

Question 63

What are 2 markers of cartilage degradation?

Answer 63

Serum and synovial keratin sulphate -increased levels indicate cartilage breakdown -Level increases with age and patients with osteoarthritis Type II collagen in synovial fluid -Increased levels indicate cartilage breakdown -Useful in evaluating cartilage erosion

Question 64

What can cause Rheumatoid arthritis?

Answer 64

Synovial cell proliferation | Inflammation

Question 65

What causes gouty arthritis?

Answer 65

Deposition of uric acid crystals

Question 66

What causes soft tissue rheumatism?

Answer 66

Injury and inflammation to periarticular structures

Question 67

What are 6 effects on the subchondral bone following cartilage wear and tear?

Answer 67

``` Thickened capsule Cyst formation Sclerosis in subchondral bone Fibrillated cartilage Synovial hypertrophy Osteophyte formation ```