Hyaline cartilage is composed of which type of fibrils –
Hyaline cartilage is one of the three main types, along with elastic and fibrocartilage. I remember that each has different structural components. Hyaline is known for being smooth and glassy, found in areas like the trachea and articular surfaces. The matrix of hyaline cartilage is rich in collagen. But what type of collagen? There are different types of collagen fibers in the body. Type I is in skin and bones, Type II is in cartilage, Type III in reticular fibers, Type IV in basement membranes, and Type V in various tissues.
So hyaline cartilage should have Type II collagen fibrils. Let me confirm: yes, hyaline cartilage is characterized by a matrix containing type II collagen fibers. The other cartilage types might have different collagens. For example, fibrocartilage has Type I and II, while elastic cartilage has elastic fibers along with Type II.
The options given here are missing, but the correct answer is Type II. The distractors might include Type I, III, IV, or V. Each of these is incorrect because they are found in other tissues. For example, Type I is in skin and tendons, Type III in reticular fibers, Type IV in basement membranes, and Type V in small blood vessels and skin. So the correct answer is Type II collagen fibrils.
**Core Concept**
Hyaline cartilage is the most common cartilage type, characterized by a matrix containing **type II collagen fibrils**. This collagen type provides structural integrity while maintaining the cartilage's flexibility and resilience.
**Why the Correct Answer is Right**
Hyaline cartilage matrix is composed of **type II collagen**, which forms a network of fine fibrils. These fibrils are embedded in a proteoglycan-rich matrix (e.g., aggrecan), creating a gel-like structure that resists compression. The absence of elastic fibers and sparse collagen network gives hyaline cartilage its translucent appearance under microscopy. Type II collagen is synthesized by chondroblasts and is crucial for maintaining cartilage elasticity in joints, trachea, and costal cartilages.
**Why Each Wrong Option is Incorrect**
**Option A: Type I collagen** – Found in skin, tendons, and bone; absent in hyaline cartilage.
**Option B: Type III collagen** – Forms reticular fibers in organs like the liver and spleen; not present in cartilage.
**Option C: Type IV collagen** – Constitutes basement membranes (e.g., glomeruli); irrelevant to cartilage.
**Option D: Type V collagen** – Found in small blood vessels and skin; does not contribute to cartilage structure.
**Clinical Pearl / High-Yield Fact**
**"Type II is the key to cartilage's 'cushion'!"** Remember that hyaline cartilage (and articular cartilage) relies on **type II collagen** for load-bearing and shock absorption. Confusing collagen types is a common NEET/USMLE trap—focus on tissue-specific roles (e.g., Type I = skin/bone;