MICROANATOMY

Detailed explanation-1: -The organic matrix of bone is composed of collagen and non-collagenous organic materials. Collagen comprises about 90% of the organic bone matrix. Type I collagen is the most abundant form of intrinsic collagen found in the bone that is secreted by osteoblasts.

Detailed explanation-2: -The osteoblasts secrete the organic matrix, which are dense collagen layers that alternate parallel and orthogonal to the axis of stress loading. Into this matrix is deposited extremely dense hydroxyapatite-based mineral driven by both active and passive transport and pH control.

Detailed explanation-3: -The organic portion of the bone matrix consists of collagen fibers (type I), proteoglycans, and glycoproteins (e.g. osteonectin and osteocalcin). The organic material is produced and secreted by the osteoblasts.

Detailed explanation-4: -Osteoprogenitor cells are the ‘stem’ cells of bone, and are the source of new osteoblasts. Osteoblasts, lining the surface of bone, secrete collagen and the organic matrix of bone (osteoid), which becomes calcified soon after it has been deposited. As they become trapped in the organic matrix, they become osteocytes.

Detailed explanation-5: -Osteoblasts are bone cells that are responsible for bone formation. Osteoblasts synthesize and secrete the organic part and inorganic part of the extracellular matrix of bone tissue, and collagen fibers. Osteoblasts become trapped in these secretions and differentiate into less active osteocytes.