Question

Inflammation of the synovial joints in rheumatoid arthritis includes this change in the synovial fluid. a. Influx of macrophages and activated T cells b. Loss of byaluronic acid c. Thinning of the synovial membrane d. Presence of the bacterium Klebsiella 6\. HLA B27 allele has been identified in those at greater risk for all except this autoinmune disease.

Short answer

Answer: The characteristic change in synovial fluid during the inflammation of synovial joints in rheumatoid arthritis is the influx of macrophages and activated T cells.

Step-by-step solution

Understand rheumatoid arthritis and synovial fluid

Rheumatoid arthritis is an autoimmune disease that causes chronic inflammation of the synovial joints. The synovial fluid is a thick, viscous fluid found in the synovial joints, which lubricates the joint and provides nutrients to the joint cartilage.

Examine each option

We'll now examine each of the given options: a. Influx of macrophages and activated T cells - The immune system plays a crucial role in rheumatoid arthritis, and these immune cells contribute to the inflammation and destruction in joint tissues. b. Loss of hyaluronic acid - Hyaluronic acid is a key component of synovial fluid and contributes to its lubricating properties. In the setting of rheumatoid arthritis, hyaluronic acid concentration might be reduced, but this is not the primary characteristic change. c. Thinning of the synovial membrane - Thinning of the synovial membrane is not a characteristic change during inflammation in rheumatoid arthritis. Instead, the synovial membrane thickens due to an increase in immune cell infiltration and proliferation of synovial cells. d. Presence of the bacterium Klebsiella - Rheumatoid arthritis is an autoimmune disease, not an infection caused by a bacterium like Klebsiella.

Identify the correct answer

Based on the analysis in Step 2, the correct answer is (a) Influx of macrophages and activated T cells. This option best describes the change in synovial fluid during the inflammation of synovial joints in rheumatoid arthritis.

Key concepts

Synovial Joints

Synovial joints are the most common type of joints in the human body, allowing for a wide range of movements. These joints are characterized by a cavity filled with synovial fluid. They are designed to reduce friction between the articular cartilage of synovial bones during movement.
The key components that make up synovial joints include:

• A synovial membrane that lines the joint and secretes synovial fluid.
• Articular cartilage that covers the ends of bones in the joint.
• A fibrous capsule that encloses the entire joint and maintains its integrity.

The smooth operation of synovial joints is vital for healthy movement, and any dysfunction, such as inflammation, can lead to severe problems. This inflammation is especially notable in conditions like rheumatoid arthritis, where the joint lining becomes thickened and inflamed.

Immune System in Autoimmune Diseases

In autoimmune diseases, the immune system mistakenly attacks the body’s own tissues. Rheumatoid arthritis is a classic example. Here, the immune system targets the synovial membrane, leading to chronic inflammation. This attack is due to a mix of genetic, environmental, and immunological factors.
Key players in this process include:

• Macrophages and activated T cells, which invade the synovial membrane, driving inflammation.
• B cells that can produce antibodies targeting the body's own tissues.
• Pro-inflammatory cytokines that amplify the destructive inflammatory response.

The continuous presence of these immune cells in the synovial joints leads to the destruction of joint tissue, pain, and decreased mobility in rheumatoid arthritis.

Synovial Fluid Composition

Synovial fluid is a critical component of joint health, acting as a lubricant and nutrient carrier. It is a viscous, slippery fluid produced by the synovial membrane, and its composition is tailored to maintain joint functionality.
The main components of synovial fluid include:

• Hyaluronic acid, which gives the fluid its viscous, lubricating properties.
• Lubricin, which helps protect the cartilage surfaces in the joint.

In rheumatoid arthritis, the composition of synovial fluid alters. The reduction of hyaluronic acid and influx of immune cells are notable changes. This not only affects lubrication but also contributes to joint inflammation and damage.