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Arthritis

Partnership for Environmental Education and Rural Health

Texas A&M University

http://peer.tamu.edu

3Who knows what arthritis is?

• Do you know anyone that has arthritis?

– Both humans and animals can get arthritis.

• What is arthritis?

– Arthritis is the inflammation of joints.

• What are joints? Why do we have them?

3Why do we have joints?

• What would your life be like without joints?

– Try to write your name on a piece of paper without bending any joints.

– Try to jump up and down without bending your knees.

• The joints that allow you to move are called synovial joints.

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Cartilage

Joint Capsule

Synovial Fluid

Parts of A Synovial Joint

• Let’s talk about each part separately.

Bone

Ligament

3Bone

• Bone is a living tissue.

• Bone is constantly remodeling itself… what does that mean?

– Many cells exist in our bones

• Osteoclasts: Cells that ‘eat’ bone tissue

• Osteoblasts: Cells that ‘make’ bone tissue

• Osteocytes: Old osteoblasts surrounded by “bone tissue”

3What makes up bone tissue?

• Inside your bone is inorganic material containing calcium and other elements.

• That means your bones are the body’s calcium reserve.

• You body needs calcium to grow but if it isn’t getting enough from food, the osteoclasts will speed up and chew away bone to release the stored calcium faster than the osteoblasts can store it.

3Joint Capsule

• A membrane or sac that surrounds the joint• It helps hold all the parts of the joint together• Consists of two membranes or layers:

– Fibrous Membrane: The outer layer which is thick and tough and hold the joint together

– Synovial Membrane: The inner layer which secretes the synovial fluid

3Cartilage

• A thin layer of cartilage lies on the ends of the bones. It’s smoothness prevents friction.

• Cartilage is also elastic and compressible, allowing it to absorb shock.

• Cartilage is a living tissue but lacks blood vessels so the nutrients it needs are delivered by synovial fluid.

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Synovial Fluid

• Synovial fluid lubricates your joints like oil helps a car.

• This prevents the cartilage from wearing out too quickly and allows for smooth movement of the joint.

• Synovial fluid also transports nutrients to the cartilage.

3Ligaments

• Ligaments are tough, fibrous bands that connect bones to bones.

• Many joints, like your knee, require their strong support to function properly.

3Changes

• Each part of the joint has an important job to do. If any part of a joint changes, it can make it difficult for that joint to function properly.

• Some examples of bad changes include:– Cartilage can become worn out and thin.– Synovial fluid can become thinner, decreasing

the ability of the joint to slide freely.– Ligaments can be torn or damaged by excessive

exercise or sudden trauma so that they fail to support the joint.

3 What is arthritis?

• Do you remember the definition of arthritis?

• What are some things that can cause inflammation?

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Infectious Arthritis

• Typically caused by bacteria. • The bacteria may enter the body and travel

through the bloodstream to the joint, or bacteria may be directly “injected” into a joint by trauma.

• The bacteria infect the synovial fluid, causing inflammation, swelling, pain and fever.

• This type of arthritis can be treated by antibiotics and other drugs. If treated promptly, patients typically recover, although permanent damage may be done to the joint.

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Cartilage

Joint Capsule is inflamed

Synovial Fluid is infected

Infectious Arthritis

Bone

3Infected vs. Normal Talus Joint

Thin bone

Thickened, inflamed joint capsule Normal joint capsule

Normal bone

3Immune-Mediated Arthritis

• Occurs when the immune system targets the body’s protein instead of germs.

• Why this happens is unknown. • There is no cure for immune-mediated arthritis, although there are treatments

which reduce the symptoms. Fortunately, this is a rare disease in animals.• Unfortunately, this disease occurs more commonly in people and is called

rheumatoid arthritis.

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Cartilage is destroyed

Joint Capsule is inflamed

Synovial Fluid is thin

Immune-Mediated Arthritis

Bone is exposed and/or damaged

3Osteoarthritis

• Osteoarthritis, also known as degenerative joint disease, is the most common type of arthritis.

• Osteoarthritis occurs most to older animals and humans.

• Over time, the cartilage in the joint is broken down.

• As the cartilage is lost, the bones are exposed and may rub together, causing pain and more damage. The joint may have varying degrees of swelling, joint scarring, and restricted motion.

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Cartilage is worn away

Joint Capsule

Synovial Fluid with bone fragments

Osteoarthritis

Bone is worn away

3 Degenerative Joint Disease of the Pastern

Collapsed jointspace

New bone formation

Normal jointspace

3Who gets Arthritis?

Up to 1 out of every 5 dogs may be affected by arthritis.

Severe arthritis in horses can lead to an inability to perform their jobs or live comfortably. Many people feel the same way!

Similarly, 1 in 5 American adults have been diagnosed with arthritis. That’s 43 million people!

Up to 1 out of every 5 dogs may be affected by arthritis.

Similarly, 1 in 5 American adults have been diagnosed with arthritis. That’s 43 million people!

3Why study Arthritis?

• Those with arthritis may have difficulty performing tasks such as walking, climbing stairs and kneeling.

• Often times people with arthritis have a hard time participating in social activities and many end up depressed.

• Try to imagine how your life would be different if you had arthritis?

3Researching Arthritis

• Scientists are researching arthritis to discover:

– tools that aid in diagnosing arthritis

– treatments that work to alleviate the symptoms of arthritis.

– drugs that may help prevent, slow down, or reverse joint damage.

3Animals in Research

• Animal and human arthritis have much in common. This allows scientists to use animals to learn about human arthritis.

• Dogs were used to develop and study knee and hip replacements.

• Rodents studies were used to understand rheumatoid arthritis.

• Today’s studies are providing information that can help both arthritic animals and humans in the future!

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Questions?