arthritis and ATH

Question 1

osteoarthritis

Answer 1

the most common type of joint disease. a degenerative joint disease - a breakdown of the cartilage matrix

Question 2

structure of the synovial joint

Answer 2

-synovial membrane
-articular cartilage
-synovial fluid
-joint capsulesy

Question 3

synovial membrane

Answer 3

a special type of biological membrane without an epithelium. Inner lining is provided by synovial lining macrophages and synovial fibroblasts (synoviocytes)

Question 4

synoviocytes

Answer 4

synovial fibroblasts that produce synovial fluid

Question 5

synovial fluid contains

Answer 5

• inflammatory and immune cells
• is high in glucose (3.5-5.5mm/l) to nourish and feed the avascular chondrocytes.
• hyaluronic acid makes the fluid viscous and slippery

Question 6

synovial fluid functions

Answer 6

• provides nutrients for cartilage
• acts as a lubricant
• lessens the impact of mechanical forces exerted on the joint

Question 7

Articular cartilage

Answer 7

• a hyaline cartilage
• contains chondrocytes that sit in lacunae
• avascular, and thus has no capacity to regenerate after damage

Question 8

hyaline cartilage

Answer 8

allows a virtually frictionless movement of synovial joints as it is resistant to both tension and compression due to type II collagen and Proteoglycans respectively.
it has a relaxation and compression function promoting the movement of water in and out of the cartilage, allowing the survival of chondrocytes

Question 9

collagen

Answer 9

collagens are extremely strong and resistant to normal shearing and tearing forces.
- it is the most abundant protein in the human body

Question 10

proteoglycans

Answer 10

attached to long filaments of hyaluronic acid, attached by a link protein.

Question 11

aggrecan

Answer 11

building structure of hyaline cartilage ground substance.
- Proteoglycans-link protein-hyaluronic acid

Question 12

hyaline substance ground substance structure

Answer 12

the collagen fibres of type II collagen binds electrostatically to the sulphated side chains of the aggrecan.
- this forms a strong elastic material

Question 13

primary (idiopathic) arthritis

Answer 13

no apparent initiating cause and mostly oligoarticular (only one or a few joints are affected)
- 95% of all cases

Question 14

secondary osteoarthritis

Answer 14

occurs in younger individuals with some predisposing condition

Question 15

steps in developing osteoarthritis

Answer 15

1. chondrocyte injury (driven by genetic and biochemical factors) (early osteoarthritis)
2. chondrocytes proliferate and secrete inflammatory mediators, collagens, and proteases -> cartilaginous matrix remodelling
3. chondrocytes get hypertrophic and form clusters (cloning)
4. matrix metalloproteinases degrade type II collagen
5. chondrocytes continuously synthesize and secrete proteoglycans, but degradation exceeds synthesis, and the composition of proteoglycans also changes
6. the water content of the matrix increases = concentration of proteoglycans decreases
7. The physiologically horizontally arranged collagen fibres in the superficial zone are cleaved, producing fissures and clefts at the articular surface, making it soft and granular.
8. repetitive injury and chronic inflammation lead to chondrocyte drop out, secondary inflammatory changes in the synovium and subchondral bone

Question 16

step 1 osteoarthritis

Answer 16

chondrocyte injury (driven by genetic and biochemical factors)

Question 17

step 2 osteoarthritis - early osteoarthritis

Answer 17

chondrocytes proliferate and secrete inflammatory mediators, collagens, and proteases -> cartilaginous matrix remodelling

Question 18

step 3 osteoarthritis

Answer 18

chondrocytes get hypertrophic and form clusters (cloning)

Question 19

step 4 osteoarthritis

Answer 19

matrix metalloproteinases degrade type II collagen

Question 20

step 5 osteoarthritis

Answer 20

chondrocytes continuously synthesize and secrete proteoglycans, but degradation exceeds synthesis, and the composition of proteoglycans also changes

Question 21

step 6 osteoarthritis

Answer 21

the water content of the matrix increases = concentration of proteoglycans decreases

Question 22

step 7 osteoarthritis

Answer 22

The physiologically horizontally arranged collagen fibres in the superficial zone are cleaved, producing fissures and clefts at the articular surface, making it soft and granular.

Question 23

step 8 osteoarthritis

Answer 23

repetitive injury and chronic inflammation lead to chondrocyte drop out, secondary inflammatory changes in the synovium and subchondral bone

Question 24

bone eburnation

Answer 24

• exposed subchondral bone plate becomes the new articular surface.
• friction with the opposing surface smooths and burnishes the exposed bone, giving it the appearance of polished ivory

Question 25

fibrous-walled cysts

Answer 25

created from small fractures in the bone create gaps, allowing the synovial fluid into the subchondral regions

Question 26

ostephytes

Answer 26

mushroom-shaped bony outgrowths that develop at the margins of the articular surface and are capped by fibrocartilage and hyaline cartilage that gradually ossify

Question 27

heberden's node

Answer 27

prominent osteophytes at the distal interphalangeal joints; common in women.

Question 28

rheumatoid arthritis

Answer 28

a chronic inflammatory disorder of autoimmune origin. may attack tissues or organs, but principally attacks joints, producing a nonsuppurative proliferative and inflammatory synovitis

Question 29

ankolysis

Answer 29

fusion of joints

Question 30

nonsuppurative

Answer 30

no pus is formed

Question 31

inflammatory synovitis

Answer 31

inflammation of the synovial membrane

Question 32

Specific class II MHC alleles (HLA-DR4) sharing a consensus QKRAA motif in the peptide-bonding groove

Answer 32

have been highly related to disease susceptibility and to greater severity in RA

Question 33

T cells

Answer 33

produce cytokines that stimulate other inflammatory cells to effect tissue injury (TNF and IL-1)

Question 34

TNF and IL-1

Answer 34

stimulate resident synovial cells to secrete proteases that destroy hyaline cartilage

Question 35

inflammatory process in RA leads to

Answer 35

the synovial membrane thickens and accomodates numerous B and T cells, macrophages and vascular changes. The enlarged synovial tissue invades and destroys adjacent cartilage and bone

Question 36

pannus

Answer 36

a mass of oedematous synovium, inflammatory cells, granulation tissue, and fibroblasts that grows over the articular cartilage and causes its erosion

Question 37

atherosclerosis

Answer 37

a chronic inflammatory and healing response of the arterial wall to endothelial injury

Question 37

tunica intima

Answer 37

epithelial lining of blood vessels that can produce several substances that cause vasodilation or vasoconstriction

Question 38

tunica media

Answer 38

circumferential smooth muscle of the blood vessel

Question 39

tunica externa

Answer 39

CT support: contains the blood vessels own supply of bv and nerve supply

Question 40

initiating event of athersclerosis

Answer 40

endothelial damage, mainly due to turbulent flow and/or hypertension