Brosk

Brosk is the Swedish term for cartilage, a flexible connective tissue that provides structural support, cushions joints, and helps shape certain body parts such as the nose and ears. In humans, cartilage is largely avascular and aneural, and its metabolism depends on surrounding tissues for nutrients and signaling.

Cartilage consists mainly of chondrocytes embedded in an extracellular matrix rich in collagen type II and proteoglycans, with high water content that gives resistance to compression. Most cartilage is enclosed by a perichondrium, a fibrous layer that supplies nutrients in non-articular regions; articular cartilage at joints is typically avascular and lacks a true perichondrium.

Cartilage is classified into three main types: hyaline cartilage, elastic cartilage, and fibrocartilage. Hyaline cartilage covers articular surfaces of bones and is found in the rib cage, nose, trachea, and larynx. Elastic cartilage contains elastic fibers and is present in the external ear and epiglottis. Fibrocartilage has thick collagen fibers and appears in intervertebral discs, the pubic symphysis, and menisci.

Growth and development of cartilage involve chondrogenesis, with interstitial and appositional growth contributing to size and shape changes. Cartilage can be replaced by bone through endochondral ossification during development, while mature articular cartilage has limited regenerative capacity.

Clinical relevance includes injuries and degenerative conditions such as osteoarthritis, which involve loss of articular cartilage and impaired joint function. Chondromalacia patellae and chondrosarcoma are other cartilage-related conditions. Research in cartilage biology and tissue engineering seeks improved repair and replacement strategies.