Joints, Cartilage and Synovial Fluid

Question 1

structural classification of joints

Answer 1

fibrous
cartilagenous
synovial

Question 2

give examples of fibrous joints

Answer 2

periodontal ligament
cranial sutures
interosseous membranes

Question 3

name the two types of cartilaginous joints

Answer 3

primary - synchondrosis

secondary - symphysis

Question 4

what type of cartilage is found in a primary cartilaginous joint?

Answer 4

hyaline cartilage

Question 5

what type of cartilage is found in a secondary cartilaginous joint?

Answer 5

hyaline and fibrocartilage

Question 6

give examples of secondary cartilaginous joint

Answer 6

midline - IV discs, pubic symphysis, manubriosternal

Question 7

common features of synovial joints

Answer 7

cavity
articular cartilage
fibrous capsule
membrane

Question 8

what other features of synovial joints may be there?

Answer 8

Articular disc
ligaments
bursae

Question 9

what types of synovial joints are there?

Answer 9

plane/gliding
condylar - ellipsoid
hinge
saddle
pivot
ball and socket

Question 10

example of plane joint

Answer 10

IV discs

Question 11

example of condylar hoint

Answer 11

metacarpophalangeal

Question 12

example of hinge joint

Answer 12

elbow

knee

Question 13

example of saddle joint

Answer 13

carpometacarpal of thumb

Question 14

example of pivot joint

Answer 14

proximal and distal radioulnar

Question 15

example of ball and socket joint

Answer 15

hip

shoulder

Question 16

movements in a plane joint

Answer 16

1 plane

Question 17

movements in a condylar joint

Answer 17

flexion
extension
adduction
abduction
circumduction

Question 18

movements in a hinge joint

Answer 18

1 plane

Question 19

movements in a pivot joint

Answer 19

1 plane

Question 20

what factors maintain joint stability?

Answer 20

shape of the articulating surfaces
capsule
ligaments
muscles

Question 21

describe hyaline cartilage: superficial layer

Answer 21

flattened chondrocytes that produce collagen and glycoproteins e.g.lubricin

Question 22

describe hyaline cartilage: transitional layer

Answer 22

round chondrocytes that produce proteoglycans such as aggrecan

Question 23

why is 75% of hyaline cartilage composed of water?

Answer 23

cannot be compressed

Question 24

what are glycoproteins?

Answer 24

lubricin

to which oligosaccharide chains are attached

Question 25

what are proteoglycans?

Answer 25

aggrecan | proteins that are heavily glycosylated

Question 26

what is hyaluronic acid?

Answer 26

a glycosaminoglycan or GAG, is a long unbranched polysaccharide, which is highly polar and thus attracts water

Question 27

average thickness of articular cartilage?

Answer 27

2-3 mm

Question 28

why is healing of cartilage slow?

Answer 28

avascular aneural alymphatic

Question 29

what produce synovial fluid?

Answer 29

synoviocytes

Question 30

describe the synovial membrane and how this helps in function?

Answer 30

rich capillary network with no epithelial lining | allows for direct exchange of oxygen, carbon dioxide and metabolites between blood and synovial fluid

Question 31

type A synoviocytes

Answer 31

look like macrophages and remove debris | contribute to synovial fluid production

Question 32

type B synoviocytes

Answer 32

fibroblast like | main producers of synovial fluid

Question 33

describe the components of synovial fluid

Answer 33

viscous fluid containing hyaluronic acid and lubricin

Question 34

where does synovial fluid come from?

Answer 34

blood plasma

Question 35

approx how much synovial fluid is there in the knee?

Answer 35

0.5ml

Question 36

turnover of synovial fluid

Answer 36

2 hours

Question 37

functions of synovial fluid

Answer 37

provide nutrient to the cartilage and remove waste products | lubricin

Question 38

functions of glycoproteins in synovial fluid

Answer 38

bind to receptors on the articular surfaces to form a thin film which acts as a boundary for the fluid

Question 39

describe the properties of synovial fluid

Answer 39

hydrodynamic surfaces kept apart by liquid pressure viscosity of the fluid changes with load and velocity of movement

Question 40

what is weeping in regards to synovial fluid?

Answer 40

Fluid that is present in the cartilage is squeezed out into the synovial cavity to increase fluid volume. This is known as weeping.

Question 41

what are bursae and their functions?

Answer 41

synovial membranes filled with fluid to reduce friction

Question 42

effect of ageing on synovial joints

Answer 42

As we age the viscosity of synovial fluid increases leading to slower joint movements and reduced lubrication. The water content of cartilage decreases therefore there is reduced shock absorption. This all leads to less protection of articular surfaces and increased risk of damage.