Physiology of Joints

Question 1

what are bones separated by in a synovial joint?

Answer 1

cavity containing synovial unit

Question 2

what are bones united by in a synovial joint?

Answer 2

fibrous capsule
ligaments
tendons
bursae

Question 3

what is the inner aspect of fibrous capsule lined with?

Answer 3

synovial membrane

Question 4

what kind of tissue is the synovial membrane?

Answer 4

vascular connective tissue with capillary networks and lymphatics

Question 5

what kind of cells are present in the synovial membrane

Answer 5

synovial cells

Question 6

what do synovial cells do?

Answer 6

produce synovial fluid and mucin (hyaluronic acid)

Question 7

another name for synovial cells

Answer 7

fibroblasts

Question 8

another name for articular cartilage

Answer 8

hyaline cartilage

Question 9

what is the difference between a simple and compound synovial joint?

Answer 9

simple= 1 pair of articular surfaces, compound= more than 1 pair of articular surfaces

Question 10

main role of joints?

Answer 10

structural support

purposeful motion

Question 11

how do joints create stability?

Answer 11

synovial fluid

ligament attachments

Question 12

what does synovial fluid do?

Answer 12

lubricates joint,

facilitates joint movement, aids in nutrition of articular cartilage and chondrocytes

Question 13

is synovial fluid viscous or thin?

Answer 13

viscous

Question 14

why is synovial fluid viscous?

Answer 14

presence of hyaluronic acid aka mucin

Question 15

why is articular cartilage so in need of nutrients?

Answer 15

it is avascular so needs its nutrients delivered by a medium

Question 16

main cells contained in synovial fluid?

Answer 16

mononuclear leukocytes

Question 17

how does synovial fluid viscosity and elasticity change during rapid movement

Answer 17

decreased viscosity

increased elasticity

Question 18

when do polymorph levels increase?

Answer 18

inflammation

infection

Question 19

what should synovial fluid look like?

Answer 19

clear and colourless

Question 20

when would synovial fluid turn red?

Answer 20

traumatic synovial tap

haemorrhagic arthritis

Question 21

when would you suspect a synovial fluid sample was septic?

Answer 21

opaque appearance

high WBC count

Question 22

functions of articular cartilage?

Answer 22

prevents wear and tear

distributes contact pressure to subchondral bone

Question 23

which part of the articular cartilage has the highest volume

Answer 23

extracellular matrix

Question 24

4 zones of articular cartilage?

Answer 24

superficial
middle
deep
calcified

Question 25

which type of collagen contributes most to the elastic behaviour of cartilage?

Answer 25

type 2

Question 26

what makes up the major component of cartilage?

Answer 26

water

Question 27

which type of collagen decreases with age?

Answer 27

type 2

Question 28

where is most of the articular cartilage's water distributed?

Answer 28

near articular surface

Question 29

what is the role of collagen in cartilage?

Answer 29

provides stiffness and strength | maintains architecture

Question 30

where is proteoglycan found in cartilage?

Answer 30

middle and deep zones

Question 31

what is the role of proteoglycan in cartilage

Answer 31

compression i.e load bearing

Question 32

what cells maintain and organise the extracellular matrix?

Answer 32

chondrocytes

Question 33

what do catabolic factors of the ECM do?

Answer 33

stimulate proteolytic enzymes and inhibit proteoglycan synthesis

Question 34

give examples of catabolic factors of cartilage matrix turnover?

Answer 34

TNFa | IL-1

Question 35

what do anabolic factors of the ECM do?

Answer 35

stimulate proteoglycan synthesis and counteract effects of IL-1

Question 36

give examples of anabolic factors of the ECM?

Answer 36

TGF-b | IGF-1

Question 37

name markers of cartilage degradation

Answer 37

increased type 2 collagen | increased serum and synovial keratin sulfate

Question 38

what causes rheumatoid arthritis?

Answer 38

synovial cell proliferation and inflammation

Question 39

what causes soft tissue rheumatism?

Answer 39

injury and inflammation to periarticular structures

Question 40

what are the pathological effects on subchondral bone from osteoarthritis?

Answer 40

``` thickened capsule cyst formation sclerosis fibrillated cartilage hypertrophy osteophyte formation ```

Question 41

name the cell types that drill into bone

Answer 41

osteoclasts