**Question:** Hyaline cartilage contains which type of collagen?

**Core Concept:** Hyaline cartilage is a type of cartilage found in various parts of the human body, such as the nose, trachea, and ribs. It primarily consists of collagen fibers, proteoglycans, and water. There are three types of collagen in the body: types I, II, and III.

**Why the Correct Answer is Right:** Type II collagen is the predominant collagen type in hyaline cartilage, making up about 90% of its collagen content. Type II collagen is composed of alpha-1(II) and alpha-2(II) chains, which form a triple helix structure. The unique arrangement and composition of type II collagen give hyaline cartilage its characteristic elasticity and resistance to compression.

**Why Each Wrong Option is Incorrect:**

A. Type I collagen is the most abundant collagen type in the body and is typically found in connective tissues like skin and bone. It does not make up a significant portion of hyaline cartilage.

B. Type III collagen is another type of collagen found in connective tissues, but its proportion in hyaline cartilage is very low compared to type II collagen.

C. Type IV collagen is a component of the basal lamina and not present in hyaline cartilage.

**Clinical Pearl / High-Yield Fact:** Understanding the composition of hyaline cartilage is essential for understanding its biomechanical properties, which are vital for the proper functioning of structures like the trachea and nose. Injuries to these structures can lead to complications like airway obstruction and impaired sense of smell, respectively.

**Correct Answer:** D. Type II collagen