Which is the major collagen present in cartilage?
**Core Concept**
Type II collagen is the major collagen present in cartilage, making up approximately 50-80% of the total collagen in cartilage tissue. This is a critical component of the extracellular matrix, providing tensile strength and resilience to cartilage.
**Why the Correct Answer is Right**
Type II collagen is composed of a triple-helix structure, with three alpha-1(II) chains. It is secreted by chondrocytes, the cells responsible for cartilage production, and is then integrated into the cartilage matrix. The unique properties of Type II collagen allow cartilage to resist compressive forces and maintain its shape.
**Why Each Wrong Option is Incorrect**
**Option A:** Type I collagen is primarily found in skin, bone, and tendon, making it an unlikely candidate for cartilage.
**Option B:** Type III collagen is often associated with vascular tissues, such as blood vessels and the placenta, and is not a major component of cartilage.
**Option C:** Type IV collagen forms a network of basement membranes in various tissues, but is not a primary collagen in cartilage.
**Clinical Pearl / High-Yield Fact**
Remember that Type II collagen is a key component of cartilage, and its degradation is a hallmark of osteoarthritis, a common joint disorder.
**Correct Answer:** C. Type II collagen.