Synovial joints, also known as diarthroidal joints, are the most common and movable type in the body. The presence of lubricating synovial fluid encapsulated by joint ligaments distinguishes this type of joint from others within the body90. OA most commonly occurs within the weight bearing synovial joints including the hip and the knee, which is why obesity is such a major risk factor of OA4. The synovial joint can be broken down into four major components: articular cartilage, synovium, joint cavity filled with synovial fluid, and joint capsule ligament (Figure 1a) 60,115. Ultimately, articular cartilage and the synovial fluid are the main constituents that contribute to the proper lubrication properties of healthy and OA synovial joints.
3.1.1. Articular Cartilage
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Overall, articular cartilage is a very dense structure, lacking blood vessels and nerves that are found in other tissues77. Chondrocytes are the cell types embedded within cartilage, and produce the structural proteins that form the ECM. The major components of the ECM are water, type II collagens, proteoglycans, aggrecan, and noncollagenous proteins such as fibronectins115,22. The resulting osmotic pressure created within the wet and dry components of the ECM work in harmony to support the mechanical forces applied to cartilage77. The water is retained in the ECM by aggrecan, the primary structural proteoglycan which is based on a long hyaluronic acid backbone with highly charged glycosaminoglycan (GAG) side chains, such as chondroitin sulfate (CS) and keratin sulfate (KS)26. Altogether, these components are what create the depth dependent layers of cartilage: the superficial zone, the middle zone, the deep zone, and the calcified zone (Figure
12. What are the 3 types of cartilage and where would you find each type?
9. Hyaline cartilage is found on many joint surfaces, it has a very firm consistency. It contains no nerves or blood vessels, and its structure is relatively simple. Elastic cartilage, also called yellow cartilage, is present in the ears; it contains elastic fiber networks and collagen fibers. Fibrocartilage is found in the pubic symphysis, the annulus firbrosus of the intervertebral discs, menisci and the TMJ. During labor, the pubic symphysis is loosened to aid in delivery.
Cartilage tissue is a smooth, firm substance that protects ends of the bones from friction during movement and they can be found at the end of our bones in mobile joints, the front ends of the ribs, also in parts of our nose and ears.
The articular cartilage is a connective tissue that covers the part of the epiphysis where the bone comes together to form a joint, also known as an articulation. Articular cartilage allows bones to glide over each other creating very little friction and also makes it easier for
The slide below shows a section of the trachea (windpipe). Rings of hyaline cartilage embedded within the walls of the trachea provide support and help to maintain an open airway. Hyaline cartilage is the most common form of cartilage in the body, making up part of the nose, connecting ribs to the sternum, and covering the articulating surfaces of bones. When sectioned and stained, the matrix of hyaline cartilage takes on a light purple color. Cartilage-forming cells called chondroblasts produce this matrix, which consists of an amorphous ground substance heavily invested with collagen fibers. Chondrocytes (mature cartilage cells) can be seen singly or in groups within spaces (called lacunae) in
For the human joint anatomy project, our group decided to research and construct the elbow joint. The following is a report and summary of the project including roles taken, challenges faced, solutions derived, and ultimately, contribution and experiences of both partners.
The knee is a hinge-type, diarthrotic, or freely moveable joint. Also referred to as a synovial joint, the 2 articulating ends of bone are encased in a capsule that lubricates the joint with synovial fluid to reduce friction.
Unlike the knee, the articular cartilage of the ankle is uniform in thickness, measuring from 1 to 1.7mm, and displays much higher compressive stiffness than hip or knee cartilage (10,11,19,20). Ankle cartilage may develop fissures attributable to wear; this conditions does not progress to OA as it wound in the knee or hip (10,11,19, 20). Ankle cartilage also does not decrease in tensile strength with age (10,11,19-21). Compared to the hip and knee, ankle chondrocytes have different biomechanical and biologic factors to resist degradation, especially inflammatory markers. Ankle chondrocytes have decreased sensitivity to Interleukin-1 (IL-1) and matrix metalloproteinases (MMP), in particular MMP-8 that is usually elevated in OA (10,11,19, 20, 22). As a result, the ankle joint is unlikely to succumb to damage by inflammatory changes
The knee is one of the largest and most complex joints in the body. The knee has two joints the tibia (shin bone) joins the femur (thigh bone) this joint is known as the tibiofemoral joint the second joint is called patellofemoral which are joins between the kneecap and the femur. The patellofemoral and tibiofemoral works together to form the synovial hinge joint this hinge joint allows the knee to rotate a little and move side to side, it also allows the knee to be straight and bend. When standing the thigh (femur) and shin bone (tibia) locks together to form a firm component; when sitting the two bones hardly touch each other. According to HealthPages, there are five main parts of the knee joints which are bones, ligaments, tendons, cartilages
Osteoarthritis is a degenerative joint disease. It’s where flexible tissues in the end of the bones wear down. It mostly occurs in knees, hips, lower back, fingers, and the neck. In Osteoarthritis, the cartilage in the bone breaks down which causes pain, swelling, and problems in moving the joint. When it worsens over time, one can get spurs, where bones break down and develop growths. Even though this can occur in anyone, ones who are over the age of 65 will most likely get Osteoarthritis. Some risk factors will include the increasing of age, obesity, genes, weak joint muscles, previous joint injury, and the overuse of the joint in the body. Some related signs/symptoms can be swelling around a joint, stiff joint, and/or having a clicking sound
Osteoarthritis is a known joint disease and also a common arthritis. This pathological condition results from wear and tear on the joints. It begins in the cartilage where it’s smooth, slippery tissue covers the ends of the bones as they come together. As this condition worsens, the joint space becomes narrower and becomes flattened. The joints no longer have cushions and it becomes rough to where the bones are rubbing against each other.
Rheumatoid arthritis (RA) is an autoimmune disease where the body’s immune system protects the body’s health by attacking unknown substances like bacteria and viruses, and mistakenly attacks the body’s joints. This creates inflammation causing the tissue that lines the inside of joints to thicken, which results in swelling and pain in and around the joints. The tissue makes a fluid that lubricates joints and helps them move smoothly. If inflammation goes unchecked, it can damage cartilage, the elastic tissue that covers the ends of bones in a joint, as well as the bones themselves. Over time, there is loss of cartilage, and the joint spacing between bones may become smaller. Joints can become
The type of joint that is chronically affected is the synovial joint. The bones that are at a synovial joint are covered by articular cartilage; which reduces friction and absorbs shock. The space between the articulating bones is
Answer: TRUE Diff: 2 Page Ref: 255 21) Dislocations in the TMJ almost always dislocate posteriorly with the mandibular condyles ending up in the infratemporal fossa. Answer: FALSE Diff: 2 Page Ref: 268-269 22) Symphyses are synarthrotic joints designed for strength with flexibility. Answer: FALSE Diff: 2 Page Ref: 251 Multiple-Choice Questions 1) A fibrous joint that is a peg-in-socket is called a ________ joint. A) syndesmosis B) suture C) synchondrosis D) gomphosis Answer: D Diff: 2 Page Ref: 250 2) The cruciate ligaments of the knee ________. A) tend to run parallel to one another B) are also called collateral ligaments C) prevent hyperextension of the knee D) assist in defining the range of motion of the leg Answer: C Diff: 2 Page Ref: 263-264 3) Articular cartilage found at the ends of the long bones serves to ________. A) attach tendons B) produce red blood cells (hemopoiesis) C) provide a smooth surface at the ends of synovial joints D) form the synovial membrane Answer: C Diff: 1 Page Ref: 251
Synovial joints are the most common joints in the skeletal system and are also known as the freely moveable joints. They are not directly connected which is why it allows a great amount of movement. As with most other joints in the body, synovial joints achieve more movements. The synovial joints consist of six different types of joints.