Name the outer connective tissue layer that envelops some hyaline cartilage.
The correct answer and explanation is:
The outer connective tissue layer that envelops some hyaline cartilage is called the perichondrium.
The perichondrium is a dense layer of connective tissue that surrounds most cartilage types, including hyaline cartilage. It plays a critical role in the maintenance, growth, and repair of cartilage. The perichondrium consists of two layers: the outer fibrous layer and the inner cellular (chondrogenic) layer. The outer layer is made of dense collagen fibers that provide structural support and strength. The inner layer contains chondroblasts, which are responsible for producing new cartilage cells, aiding in the growth and repair of cartilage.
In addition to its structural function, the perichondrium acts as a source of nutrients for the cartilage. Since cartilage is avascular (lacking blood vessels), the nutrients it requires are supplied by diffusion from the perichondrium. This is crucial for maintaining the health and functionality of cartilage, especially in areas that undergo stress and require strength and flexibility.
The perichondrium is absent in certain types of cartilage, such as articular cartilage, which covers the ends of bones in synovial joints. In these areas, the lack of perichondrium is compensated by the synovial fluid, which provides nourishment and reduces friction during movement. Despite the absence of perichondrium in some regions, it is essential in supporting the growth and repair of hyaline cartilage in other parts of the body, such as in the costal cartilage of ribs or in the nasal cartilage.
Understanding the role of the perichondrium is important in fields like orthopedics and regenerative medicine, where the ability to repair and regenerate cartilage is a significant concern.