Cartilage is primarily made of specialized cells called chondrocytes embedded in a matrix of collagen and proteoglycans, all of which are surrounded by water.
Here's a more detailed breakdown:
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Chondrocytes: These are the only cells found in cartilage. They are responsible for producing and maintaining the cartilage matrix. They reside in small spaces called lacunae within the matrix.
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Collagen: This is a strong, fibrous protein that provides cartilage with its tensile strength and structure. It's like the reinforcing bars in concrete. Different types of collagen exist, with Type II collagen being the most prevalent in hyaline and elastic cartilage, while fibrocartilage contains a significant amount of Type I collagen.
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Proteoglycans: These are complex molecules consisting of a core protein attached to glycosaminoglycans (GAGs). They are heavily hydrated and contribute to cartilage's resilience and ability to resist compression. Think of them as water-filled cushions. They form strands that interact with collagen fibers, creating a mesh-like structure.
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Water: Cartilage is a highly hydrated tissue, with water making up a significant portion of its overall composition (around 60-80%). This water is crucial for nutrient transport to the chondrocytes and for withstanding compressive forces.
In summary, cartilage is a composite material, with the chondrocytes maintaining the collagen and proteoglycan matrix that gives the tissue its unique biomechanical properties. The specific type of cartilage (hyaline, elastic, or fibrocartilage) depends on the relative amounts and organization of these components.
