óseos

Osseous tissue, or bone tissue, is a mineralized connective tissue that forms the rigid framework of the vertebrate skeleton. It supports the body, protects vital organs, enables movement in concert with muscles, stores minerals such as calcium and phosphate, and houses the bone marrow for hematopoiesis. The tissue is a composite of organic collagen type I and inorganic hydroxyapatite crystals, embedded in a water-rich matrix. The principal cell types are osteoblasts (bone-forming cells that secrete osteoid), osteocytes (mature cells embedded in lacunae that maintain bone tissue), and osteoclasts (multinucleated cells that resorb bone).

Anatomically, osseous tissue is divided into compact (cortical) bone, which forms a dense outer layer and contains osteons, and cancellous (spongy) bone, with a lattice of trabeculae that supports marrow. The outer surface is covered by the periosteum, and the inner surfaces by the endosteum; blood vessels and nerves permeate the tissue, enabling growth, nutrition, and remodeling.

Developmentally, bone forms by intramembranous ossification (direct formation from mesenchyme) and endochondral ossification (replacement of cartilage). Throughout life, bone remodeling by osteoclasts and osteoblasts reshapes the mineralized matrix, supporting growth, repair, and mineral homeostasis.

Clinically, alterations in osseous tissue underlie diseases such as osteoporosis (low bone mass and strength), osteogenesis imperfecta (defective collagen), and osteomalacia/rickets (defective mineralization).