9: Physiology of joints

Question 1

What are the three types of joint found in the body?

Answer 1

Synovial

Fibrous

Cartilaginous

Question 2

In synovial joints, bones are separated by a ___ and joined by a fibrous ___.

Answer 2

cavity

capsule

Question 3

What does a synovial cavity contain?

Answer 3

Synovial fluid

Question 4

What is the inner part of the capsule lined by?

Answer 4

Synovial membrane

Question 5

The synovial membrane is vascularised by ___.

Answer 5

capillaries

Question 6

Which cells, found in the synovial membrane, produce synovial fluid?

Answer 6

Fibroblasts

Question 7

Which parts of bone in a synovial joint are covered in hyaline cartilage?

Answer 7

Articular parts

Question 8

simple

compound

Question 9

Joints provide structural ___ to the skeleton and allow for purposeful ___.

Answer 9

support

movement

Question 10

joint lubrication

Question 11

What is the main function of synovial fluid?

Answer 11

Lubricates joint to reduce friction between articular surfaces

Question 12

Articular cartilage (hyaline) has no vascular supply.

How is it kept alive?

Answer 12

Nourished by synovial fluid

i.e supplies O₂ and removes CO₂/waste

Question 13

Synovial fluid totally fills the joint cavity - how much synovial fluid is found in the adult knee?

Answer 13

3.5ml

Question 14

Synovial fluid is constantly ___ and ___ by the synovial membrane.

Answer 14

absorbed , replenished

Question 15

Which chemical, found in synovial fluid, makes it highly viscous?

Answer 15

Hyaluonic acid (mucin)

Question 16

Does the synovial fluid contain any cells?

Answer 16

Yes, some white blood cells

and chondrocytes

Question 17

viscosity vs elasticity

Question 18

What colour is synovial fluid?

Answer 18

Clear and colourless

Question 19

When does the WBC of synovial fluid increase?

Answer 19

Inflammatory / septic arhritis

Question 20

Why may synovial fluid turn red?

Answer 20

Iatrogenic - traumatic aspiration

Haemorrhagic arthritis

Question 21

What colour does inflammatory synovial fluid turn?

Answer 21

Yellow

Question 22

Generally, the more inflamed a synovial joint is, the more (transparent / opaque) the fluid will become.

Answer 22

opaque i.e can’t see through it

Question 23

What is the main function of articular cartilage?

Answer 23

Reduces friction and pressure to prevent wear-and-tear of joints

Question 24

The vast majority of cartilage is ___ ___.

Answer 24

extracellular matrix

Question 25

What are the two "sides" of cartilage in relation to the joint cavity?

Answer 25

**Subchondral zone** - close to the bone **Articular surface** - touching cavity / other bone

Question 26

structure of articular cartilage

Question 27

What is articular cartilage usually made of?

Answer 27

**Hyaline**

Question 28

Articular cartilage is **(rigid / elastic)** and **(solid / spongy)**.

Answer 28

**elastic , spongy**

Question 29

What is the main constituent of cartilage?

Answer 29

**Water**

Question 30

Which fibre makes up 20% of cartilage and allows it to be elastic?

Answer 30

**Type II collagen**

Question 31

What makes up the other 10% of cartilage?

Answer 31

**Proteoglycans**

Question 32

Water, collagen and proteoglycans found in cartilage all **(increase / decrease)** with age.

Answer 32

**decrease**

Question 33

properties of water, collagen and proteoglycans

Question 34

What makes up 98% of the total volume of cartilage?

Answer 34

**Extracellular matrix**

Question 35

Which cells maintain the extracellular matrix of cartilage?

Answer 35

**Chondrocytes**

Question 36

Articular cartilage is **avascular**. How do chondrocytes receive oxygen?

Answer 36

**Synovial fluid**

Question 37

Normally, the rates of synthesis and degradation of ECM are \_\_\_.

Answer 37

**equal**

Question 38

Changes in the proportions of water, collagen and proteoglycans affect the ___ of cartilage.

Answer 38

**properties**

Question 39

Apart from changes in the proportions of its constituent parts, what is another cartilage-related cause of joint diseae?

Answer 39

**Rate of ECM degradation \> Rate of ECM synthesis**

Question 40

catabolic & anabolic factors

Question 41

markers of degradation

Question 42

What joint condition is caused by wear and tear of cartilage and the synovial cavity?

Answer 42

**Osteoarthritis**

Question 43

Which joint condition is caused by **synovial cell proliferation and inflammation**?

Answer 43

**Rheumatoid arthritis**

Question 44

Deposition of crystals e.g uric acid in joints causes \_\_\_.

Answer 44

**gout**

Question 45

soft tissue rheumatism