Physiology: Joints

Question 1

fibrous joints

Answer 1

• syndesmoses and sutures
• dont allow any movement

Question 2

syndesmoses example

Answer 2

interosseous membrane between tibia and fibia

Question 3

example of 1y and 2y cartilaginous joint

Answer 3

• 1y - hyaline cartilage on the end of bones
• 2y - intervertebral discs
• allow limited movement

Question 4

name 4 cartilaginous joints

Answer 4

• pubic symphysis
• intervertebral disc
• part of SI joints
• costochondral joints

Question 5

amphiarthorisis

Answer 5

cartilaginous joint

Question 6

diarthrosis

Answer 6

synovial joint

Question 7

what is the synovial membrane made up of

Answer 7

vascular connective tissue with capillary networks and lymphatics

Question 8

what does the synovial membrane do

Answer 8

contains synovial cells (fibroblast) which produce synovial fluid

Question 9

define simple synovial joint

Answer 9

one articular surface eg metacarpophalangeal joint

Question 10

define compound synovial joint

Answer 10

>1 articular surfaces eg elbow joint

Question 11

how are joints additionally supported

Answer 11

extra articular structures

Question 12

how does a joint confer stability during purposeful motion

Answer 12

shape of articular component, ligament and synovial fluid that acts as an adhesive seal

Question 13

how is joint lubrication provided

Answer 13

• cartilage interstitial fluid
• synovial fluid is made up of hyaluronic acid and lubrcin

Question 14

what does the synovial fluid supply the chondrocytes with

Answer 14

O2 and nutrients and removes Co2 and waste products

Question 15

where is the synovial fluid found

Answer 15

fills the joint cavity

Question 16

is the synovial fluid static pool or is it replenished

Answer 16

replenished and absorbed by synovial membrane

Question 17

what is the viscosity of the synovial fluid like

Answer 17

• high
• mainly due to hyaluronic acid (mucin) that is produced by synovial cells and is in the synovial fluid
• varies with joint movement

Question 18

what cells does the synovial fluid normally contain

Answer 18

few mononuclear leucocytes

Question 19

describe the relationship between synovial fluid viscosity and elasticity and joint movement

Answer 19

rapid movement is associated with decrease viscosity and increased elasticity

Question 20

describe the relationship between synovial fluid viscosity and elasticity and joint movement on a person with a diseased joint

Answer 20

properties become defective - joint is more viscose and less elastic on movement

Question 21

what does normal synovial fluid look like

Answer 21

clear and colourless

Question 22

when would synovial fluid turn red

Answer 22

traumatic synovial tap and haemorrhagic arthritis

Question 23

what is the viscosity of inflammatory synovial fluid like

Answer 23

low

Question 24

what does a high polymorph count do to the colour of synovial fluid

Answer 24

makes it cloudy

Question 25

what are the functions of articular cartilage

Answer 25

prevents wear and tear, distributes contact pressure to subchondral bone

Question 26

describe the structure of articular cartilage

Answer 26

* several zones that differ in organisation of collagen fibres and relative content of cartilage components * water is highest near the articualr surface

Question 27

what is the composition of the ECM of articular (hyaline cartilage)

Answer 27

* 75% water * 25% type II collagen fibres and proteoglycans (made from GAGs)

Question 28

what are the functions of the water in cartilage

Answer 28

maintain resiliency of tissue and contribute to nutrition and lubrication

Question 29

what happens to the water nd collagen content of cartilage with age

Answer 29

decrease

Question 30

how is water distributed in cartilage

Answer 30

unevenly - mainly near articular surface

Question 31

what is the function of collagen in cartilage

Answer 31

type II maintain cartilage architecture and provide tensile stiffness and strength

Question 32

is there more collagen or proteoglycan in cartilage

Answer 32

collagen - 20% proteoglycan - 10%

Question 33

what is proteoglycan composed of

Answer 33

* mainly GAGs * eg chondroitin sulphate * composition changes with age eg chondroiton decreases

Question 34

what is the function of proteoglycan

Answer 34

compressive properties that are associated with load bearing

Question 35

what is the ECM in cartilage made and maintained by

Answer 35

chondrocytes

Question 36

how does articular cartilage receive 02 and nutrients

Answer 36

avascular - via synovial fluid

Question 37

what substances degrade ECM

Answer 37

metalloproteinase proteolytic enzymes eg collagenase and stromelysin

Question 38

describe the rate of degradation and synthesis of ECM

Answer 38

usually balanced, joint disease occurs if degradation\>synthesis

Question 39

name 2 catabolic factors for ECM turnover

Answer 39

TNF alpha and IL 1 (cytokines)

Question 40

name 2 anabolic factors for ECM turnover

Answer 40

TGF - beta and IGF 1

Question 41

name 2 markers of cartilage degradation

Answer 41

* serum and synovial keratin sulphate * type II collagen in synovial fluid

Question 42

what do increased levels of keratin sulphate in serum and synovial fluid indicate

Answer 42

cartilage breakdown - increase in patients with OA

Question 43

what is type II collagen in synovial fluid marker useful for

Answer 43

evaluating cartilage erosion eg osteoarthritis and rheumatoid arthritis

Question 44

osteoarthritis

Answer 44

can be caused by cartilage and synovial composition and function deteriorate with age and repeated wear and tear

Question 45

what does deposition of salt (uric acid) crystals in joint cause

Answer 45

gouty arthritis

Question 46

what does synovial cell proliferation and inflammation cause

Answer 46

rheumatoid arthritis

Question 47

what does deposition of rhomboid shaped Ca pyrophosphate crystals cause

Answer 47

pseudo gout