arthritis and ATH Flashcards

1
Q

osteoarthritis

A

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

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2
Q

structure of the synovial joint

A

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

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3
Q

synovial membrane

A

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

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4
Q

synoviocytes

A

synovial fibroblasts that produce synovial fluid

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5
Q

synovial fluid contains

A
  • 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
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6
Q

synovial fluid functions

A
  • provides nutrients for cartilage
  • acts as a lubricant
  • lessens the impact of mechanical forces exerted on the joint
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7
Q

Articular cartilage

A
  • a hyaline cartilage
  • contains chondrocytes that sit in lacunae
  • avascular, and thus has no capacity to regenerate after damage
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8
Q

hyaline cartilage

A

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

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9
Q

collagen

A

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

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10
Q

proteoglycans

A

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

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11
Q

aggrecan

A

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

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12
Q

hyaline substance ground substance structure

A

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

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13
Q

primary (idiopathic) arthritis

A

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

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14
Q

secondary osteoarthritis

A

occurs in younger individuals with some predisposing condition

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15
Q

steps in developing osteoarthritis

A
  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
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16
Q

step 1 osteoarthritis

A

chondrocyte injury (driven by genetic and biochemical factors)

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17
Q

step 2 osteoarthritis - early osteoarthritis

A

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

18
Q

step 3 osteoarthritis

A

chondrocytes get hypertrophic and form clusters (cloning)

19
Q

step 4 osteoarthritis

A

matrix metalloproteinases degrade type II collagen

20
Q

step 5 osteoarthritis

A

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

21
Q

step 6 osteoarthritis

A

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

22
Q

step 7 osteoarthritis

A

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.

23
Q

step 8 osteoarthritis

A

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

24
Q

bone eburnation

A
  • 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
25
Q

fibrous-walled cysts

A

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

26
Q

ostephytes

A

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

27
Q

heberden’s node

A

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

28
Q

rheumatoid arthritis

A

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

29
Q

ankolysis

A

fusion of joints

30
Q

nonsuppurative

A

no pus is formed

31
Q

inflammatory synovitis

A

inflammation of the synovial membrane

32
Q

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

A

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

33
Q

T cells

A

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

34
Q

TNF and IL-1

A

stimulate resident synovial cells to secrete proteases that destroy hyaline cartilage

35
Q

inflammatory process in RA leads to

A

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

36
Q

pannus

A

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

37
Q

atherosclerosis

A

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

37
Q

tunica intima

A

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

38
Q

tunica media

A

circumferential smooth muscle of the blood vessel

39
Q

tunica externa

A

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

40
Q

initiating event of athersclerosis

A

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

41
Q
A