knoglen

The knoglen, Danish for "the bone," refers to the rigid organs of the skeletal system in vertebrates. Bones are composed of mineralized connective tissue, dominated by a collagen matrix reinforced with hydroxyapatite crystals. They host several cell types, including osteoblasts that build bone, osteocytes embedded in lacunae, and osteoclasts that resorb bone. Bones are surrounded by a dense connective tissue layer called the periosteum and contain an inner lining called the endosteum.

In humans, bones are categorized by shape: long bones such as the femur and humerus; flat bones like the skull and sternum; short bones such as the carpals; and irregular bones including the vertebrae. The ends of long bones are covered by articular cartilage, and joints between bones are cushioned by synovial fluid. The adult human skeleton typically contains about 206 bones, distributed between the axial and the appendicular skeleton.

Functions include structural support, protection of internal organs, and functioning as levers for movement. Bones store minerals, especially calcium and phosphorus, and house bone marrow, the site of hematopoiesis. Development begins in early life through endochondral ossification and intramembranous ossification, and bone mass is continuously remodeled by osteoblasts and osteoclasts in response to mechanical stress and hormonal signals.

Maintaining bone health involves adequate nutrition, particularly calcium and vitamin D, regular weight-bearing exercise, and avoidance of smoking and excessive alcohol. Common conditions affecting bones include osteoporosis, osteoarthritis, and fractures after trauma. Advances in imaging and treatment have improved diagnosis and management, but the knoglen remains a dynamic, lifelong component of the body's structure and metabolism.