Joints and synovial fluid

Question 1

What are the 3 main types of joints?

Answer 1

Fibrous
Cartilaginous
Synovial

Question 2

What are the 3 types of fibrous joints?

Answer 2

Suture
Syndesmosis
Gomphosis

Question 3

What are the 2 types of cartilaginous joints?

Answer 3

Synchondrosis

Symphysis

Question 4

What are the 6 types of synovial joints?

Answer 4

Saddle
Hinge
Plane
Condylar
Ball and socket
Pivot

Question 5

What is an example of a synchondrosis?

Answer 5

Epiphyseal growth plate

Question 6

What is an example of a symphysis?

Answer 6

Vertebral discs

Pubic symphysis

Question 7

What is typically found in a synovial joint?

Answer 7

Fluid filled synovial cavity
Articular cartilage
Fibrous capsule
Synovial membrane

Question 8

Give an example of a synovial plane joint

Answer 8

Intervertebral joints

Question 9

Give an example of a synovial hinge joint

Answer 9

Elbow joint

Question 10

Give an example of a synovial pivot joint

Answer 10

Radio-ulnar joint

Question 11

Give an example of a synovial condylar joint

Answer 11

The atlanto-occipital joint (atlas to skull)

Question 12

Give an example of a synovial saddle joint

Answer 12

The thumb joint

Question 13

Give an example of a synovial ball and socket

Answer 13

Glenohumeral joint

Question 14

What can improve joint stability?

Answer 14

Shape of articulating surfaces
Capsule and ligaments
Muscles

Question 15

What is the superficial layer of the articular cartilage?

Answer 15

Flattened chondrocytes that produce collagen and glycoproteins

Question 16

What is the transitional layer of articular cartilage?

Answer 16

Round chondrocytes producing proteoglycans

Question 17

What are glycoproteins?

Answer 17

Proteins which have oligosaccharides attached - more protein than carbohydrate

Question 18

What are proteoglycans?

Answer 18

Heavily glycosylated proteins - More carb than protein

Question 19

What are Glycosaminoglycans?

Answer 19

Long unbranched polysaccharides which are highly polar and attract water

Question 20

Where is synovial fluid produced?

Answer 20

The synovial membrane/synovium

Question 21

What cells produce synovial fluid?

Answer 21

Synoviocytes

Question 22

How does the cartilage in synovial joints get nutrients with no vasculature?

Answer 22

There is a direct exchange of oxygen, carbon dioxide and metabolites between the blood and synovial fluid

Question 23

What are the 2 types of synoviocytes?

Answer 23

Type A and Type B

Question 24

What is the function of type A synoviocytes?

Answer 24

To remove debris and some role in synovial fluid production

Question 25

What is the function of type B synoviocytes?

Answer 25

The main producer of synovial fluid

Question 26

What is synovial fluid made up of?

Answer 26

Hyaluronic acid
Lubricin
Fluid from plasma

Question 27

What is the turnover of synovial fluid?

Answer 27

Around 2 hours

Question 28

What are the functions of synovial fluid?

Answer 28

Nutrition of cartilage
Removal of waste
Lubrication to reduce friction and wear

Question 29

How does synovial fluid provide lubrication?

Answer 29

Glycoproteins like lubricin bind to receptors on articular surfaces to form a thin film
Surfaces are kept apart by liquid pressure
Fluid present in cartilage is squeezed into the synovial cavity to increase fluid volume

Question 30

What happens to synovial joints as people age?

Answer 30

Viscosity of fluid increases resulting in slower movements and reduced lubrication
Water content of cartilage decreases reducing shock absorption