Rheumatoid Arthritis Module I A

8/8/2019 Rheumatoid Arthritis Module I A

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Inflammation in joints characterized by redness,warmth, swelling & pain.

Arthro joint, itis inflammation

Many types of arthritis, most common are: Osteoarthritis

Rheumatoid Arthritis

Psoriatic arthritis

Gouty arthritis Tubercular arthritis

Septic arthritis


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Structure that joins two or more adjacentbones of the skeleton.

Joint Classification

Fibrous (immoveable)

Cartilagenous

(partially moveable) Synovial

(freely moveable).


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Fibrous joints

This type of joint is held together by only a ligament.

Examples are where the teeth are held to their bony

sockets and at both the radioulnar and tibiofibular

joints.

Cartilagenous

These joints occur where the connection between thearticulating bones is made up of cartilage for example

between vertebrae in the spine.


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Synovial Joints

Synovial joints are by far the most common classification of

joint within the human body.

Five classes of tissue make up synovial joints:

Bone

Cartilage

Synovium

Synovial fluid

Tensile tissues:

Ligament and tendon.


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Normal articular cartilage is strategically located at the ends of bones to perform two

functions:

bathed in synovial fluid, it ensures virtually friction-free movements within the

joint; and

in weight-bearing joints, it spreads the load across the joint surface in a manner

that allows the underlying bones to absorb shock and weight without being

crushed.

These functions require the cartilage to be elastic (i.e., to regain normal architecture

after being compressed) and for it to have unusually high tensile strength.

These attributes are provided by the two major components of the cartilage: a special

type of collagen (type II) and proteoglycans, both secreted by chondrocytes.

As is the case with adult bones, articular cartilage is not static; it undergoes turnover

in which "worn out" matrix components are degraded and replaced. This balance is

maintained by chondrocytes, which not only synthesize the matrix but also secrete

matrix-degrading enzymes.

Thus, the health of the chondrocytes and their ability to maintain the essentialproperties of the cartilage matrix determine joint integrity.


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Synoviocytes - synovial liningcells

Produce degradative enzymes(collagenases).

Produce synovial fluid whichassists in lubrication of joints

& nutrition to cartilage.


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Functions:

Controls diffusion

Ingest debris

Secrete:

Immunoglobulins

lysosomal enzymes

Hyaluronate

lubricating glycoproteins

Reduces friction in joint


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Highly viscous fluid synthesized by synovial lining cells.

It contains:

Hyaluronate (hyaluronic acid)

Glycoprotein called lubricin


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Two functions:

Nutrition: Synovial fluid is the medium by whichnutrients are carried to & wastes are carried from,

the avascular components of the joint.

Lubrication: Hyaluronic acid is important for thelubrication of the joint capsule while lubricin is

necessary for cartilage lubrication.


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Consists of cartilage cells & cartilaginous matrix.

Cartilaginous matrix is composed of:

Collagen-II fibers: maintain the structural integrity of thetissue

Proteoglycans: highly viscous & hydrophilic, provide the

resiliency of the articular cartilage & contribute to the

lubrication of the weight bearing surfaces.

Cartilage is avascular, contains no nerves.


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Provides low friction surface

Contains type II collagen (tensile strength)

Proteoglycan having water holding capacity

Collagen meshwork entraps proteoglycans to produce a

fiber-reinforced hydrated gel which resists compression.

Collagen & Proteoglycan turnover depends on balance

between many enzymes.

When proteoglycans are lost, cartilage softens &

loosed its resilience.


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Joint ligaments: Collagen fibers

joining one bone to the other.

Joint tendon & bursae: Tendons join muscles with

bone.

Bursae: areolar tissue seen

over areas of friction (betweenmuscles & tendons).

inflamed Bursae & tendon:

(bursitis & tenosynovitis)


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Chronic, systemic inflammatory disorder

Principally attacks synovial joints.

Produces an inflammatory response of thesynovium (synovitis).

Destruction of articular cartilage & ankylosis of the

joints.

Disabling and painful condition.

Lead to substantial loss of functioning and mobility.


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This symmetry

helps distinguish

RA from other

arthritis.


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Highly inflammatory polyarthritis.

Leading to joint destruction, deformity & loss of

function. Symmetric swelling of peripheral joints is the

hallmark of the disease.

Extra-articular features & systemic symptoms

commonly occurs.


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About 1-2% of the world's population is affected.

women three times more often than men.

Onset is between the ages of 40 & 50, but people ofany age can be affected.

Prevalence increases with age, approaching 5% in

women over age 55.

Have a genetic predisposition.


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Ability to resist/avoid infection, disease, by means of

antibodies & WBC.

Humoral immunity: mediated by antibodies by B-cells.

Cellular immunity: cells like macrophages, T- cells, & the

release of cytokines in response to an antigen.

Auto-immunity: Failure of an organism to recognize its own

parts as "self", results in an immune response against its owncells. Any disease results from such an abnormal immune

response is called autoimmune disease.


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Immunity

Innat a tiv

Physical Ch mical Inflammation

Cellular Humoral


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When a monocyte enters damaged tissue through the blood vessel it become a macrophage


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Lymphocytes

T cells B cells Natural killer cells

Helper T

cells(CD4+)

Cytotoxic

T Cells(CD8+)

Memory T

cellsRegulatory

T cells(suppressor

T cells)

Natural Killer Cells

(Nk cells)

(Cell mediated immunity) (Antibody formation)

CD= cluster of differentiation


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Rheumatoid Arthritis Module I A

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