Which structure surrounds cartilage and contains progenitor cells?

Which structure surrounds cartilage and contains progenitor cells?

• A. Endosteum
• B. Perichondrium
• C. Periosteum
• D. Dermis

Answer: (B)

Cartilage is surrounded by a specialized sheath called the perichondrium. This layer has an outer fibrous portion and an inner cellular portion that houses chondrogenic progenitor cells. These progenitor cells can differentiate into chondroblasts and then chondrocytes, which build and repair cartilage. The perichondrium is especially important for growth at the surface (appositional growth) because it supplies new cells to the cartilage. Since cartilage lacks blood vessels, nutrients reach it by diffusion from the perichondrium, making this surrounding tissue essential for nourishment and repair. Structures like the endosteum and periosteum surround bone, not cartilage, and the dermis is a skin layer, so they don’t fit the description.

Cartilage is surrounded by a specialized sheath called the perichondrium. This layer has an outer fibrous portion and an inner cellular portion that houses chondrogenic progenitor cells. These progenitor cells can differentiate into chondroblasts and then chondrocytes, which build and repair cartilage. The perichondrium is especially important for growth at the surface (appositional growth) because it supplies new cells to the cartilage. Since cartilage lacks blood vessels, nutrients reach it by diffusion from the perichondrium, making this surrounding tissue essential for nourishment and repair. Structures like the endosteum and periosteum surround bone, not cartilage, and the dermis is a skin layer, so they don’t fit the description.