W32 Physiology and Pharmacology of Arthritis (RT) Flashcards
Skeletal Joints:
What are the different types?
What are the features of a synovial joint?
- Adult body – 206 bones
- Virtually all connected to other bones
- Joints
-Stable – allow little movement
-Less stable – articulating
Structural differences
1. fibrous joint - bones joined by fibrous connective tissue
2. cartilaginous joint - bones joined by hyaline cartilage or fibrocartilage
- Synovial joint - articulating surfaces of the bones not directly connected
* Contact each other within a joint cavity that is filled with a lubricating fluid
* Allow for free movement between the bones
* Most common joints of the body
Features of Synovial Joint:
- Joint cavity
- Articular cartilage
-Bone protection - Fluid filled
-Synovial – lubrication and nutrition - Articulating bone surfaces not directly
connected to each other with fibrous
connective tissue or cartilage - Allows smooth movement and increased joint mobility
- Bones connected by ligaments
-Fibrous connective tissue -support
Types of synovial joints?
- Pivot Joint
- Hinge Joint
-Elbow, knee
-Bending and straightening - Condyloid Joint
-Shallow depression - Saddle Joint
-2 planes - Plane Joint
- Flat- slide
- Ball-and-Socket Joint
-Rounded head of one bone sits into concave socket
-Greatest range of motion
-Hip
Synovial joints – more details
Articular disc / meniscus
* fibrocartilage structure located between the articulating bones
* May provide structure
* or
* Shock absorption (knee)
Bursa
* Just outside joint
* thin connective tissue sac
* filled with lubricating liquid
* Prevent friction
What is Bursitis?
Inflammation of a bursa near a joint
* pain, swelling
* Joint stiffness
* Most common - shoulder, hip, knee, or elbow joints
* Acute or chronic
-from muscle overuse, trauma, excessive or prolonged pressure on the skin, rheumatoid arthritis, gout, or infection of the joint
-Antibiotics
-NSAIDs
-Corticosteroids
What is Arthritis?
What are the different types? (4)
Arthritis
* common disorder of synovial joints
* inflammation of the joint
* Pain, swelling, stiffness, reduced joint mobility
Different types
* Osteoarthritis
* Gout (acute)
* Rheumatoid arthritis (chronic)
* Systemic lupus erythematosus (chronic)
Osteoarthritis:
Commonly due to?
Risk factors?
Most common
* Associated with aging
* Damage to the articular cartilage
Hyaline cartilage
* Matrix secreted by chondrocytes
* Avascular tissue (no blood supply)
-Slow healing
- OA
- Most idiopathic
Risks - Age
- Gender F>M
- Genetics (interleukins / COX enzymes
- Obesity
- Joint misalignment
- Injury
Features of Cartilage:
- No nerves blood vessels or lymph vessels
- Water (75%) collagen (type II) and proteoglycans
-Change shape to bear weight (compressive stress), decrease friction - Cartilage integrity- balance between metabolic and catabolic activity of
chondrocytes - Mechanical stimulation affects functioning of chondrocytes
- Physiological
-Stimulates proper functioning
Mechanical overload
* Promote matrix degradation
* Inflammatory mediators (Interleukins)
* Matrix degrading enzymes – MMPS (matrix metaloproteases)
OA - pathology
Loss of matrix in cartilage:
* Disruption of cartilage
* Swelling
* Fissures of surface
* Subchondral (bone below cartilage)
bone becomes more vascular
-New bone laid down
-Osteophpytes
-Loss of bone (less than RA)
Pain during physical activity
* In early stages relieved by rest
* Treatments – generally symptomatic –
analgesics
OA summary
Articular cartilage layer wears down:
-more pressure is placed on the bones
-increasing production of the lubricating synovial fluid
* swelling of the joint cavity – pain
* Underlying Bone Tissue thickens/grows
* →Rough bone surface
* Eventually decreased joint space
* Joint movement becomes painful
What is Rheumatoid Arthritis? (RA)
What is the primary immune response involved in rheumatoid arthritis?
- Chronic systemic autoimmune condition
-Most often fingers / wrists
-Inflammation of multiple peripheral joints
-F>M - Immune response
- Abnormal activation of B-cells and T-cells and other effectors such as macrophages
- Synovium particularly affected
- Inflammation and abnormal proliferation of synovial lining
- Pannus formation - formation of a destructive type of tissue
-invades at the interface between cartilage and bone - MMPs released by chondrocytes and osteoclasts
-Degrade cartilage and bone
-leading to joint deformity and disability - Systemic disturbance is common
General fatigue, malaise and weight loss - Extra-articular
Eg neuropathy
What contributes to the maintenance of rheumatoid arthritis?
What 2 antibodies may be detected?
Autoimmune processes play a significant role in the maintenance of rheumatoid arthritis (RA), but the exact trigger for its initiation is unclear.
•Rheumatoid factor antibodies
•Anti cyclic citrullinated protein (CCP) antibodies
What are the two autoantibodies that may be detected in rheumatoid arthritis (RA)?
- Rheumatoid factor antibodies
- anti-cyclic citrullinated protein (CCP) antibodies
- these autoantibodies are characteristic of rheumatoid arthritis (RA) but are not always present. They may be detected in the plasma before symptoms manifest.
- Their role if any in initiating the disease is unclear
How does the inflammatory response differ between acute and chronic rheumatoid arthritis (RA)?
In acute rheumatoid arthritis (RA), the inflammatory response is self-limiting, and the immune system removes the initiating stimulus. However, in chronic RA, the initiating factor may be already remote, reflecting the immune system’s ability to remember previously encountered antigens and respond inappropriately
What is the proposed theory regarding the initiation of rheumatoid arthritis (RA)?
According to the proposed theory, an unknown antigen binds to antigen-presenting cells (APCs), leading to the activation of T cells. Subsequently, activated T cells produce inflammatory cytokines, such as interferon gamma, which stimulate a variety of cells including B cells, macrophages, fibroblasts, chondrocytes, and osteoclasts.
