MICROANATOMY

Detailed explanation-1: -During bone resorption, the osteoclasts resorb the bone surface forming depressions known as Howship’s lacunae.

Detailed explanation-2: -Osteoclasts resorb bone through the production of proteolytic enzymes and secretion of hydrogen ions into the localized microenvironment under the ruffled border. This extracellular lysosome that is formed beneath the ruffled border results in degradation of collagen and calcified matrix.

Detailed explanation-3: -The remodeling cycle consists of three consecutive phases: resorption, during which osteoclasts digest old bone; reversal, when mononuclear cells appear on the bone surface; and formation, when osteoblasts lay down new bone until the resorbed bone is completely replaced.

Detailed explanation-4: -The osteoclasts are multi-nucleated cells that contain numerous mitochondria and lysosomes. These are the cells responsible for the resorption of bone. Osteoblasts are generally present on the outer layer of bone, just beneath the periosteum. Attachment of the osteoclast to the osteon begins the process.

Detailed explanation-5: -The osteoclasts secrete hydrogen ions, collagenase, cathepsin K and hydrolytic enzymes into this compartment. Resorption of bone matrix by the osteoclasts involves two steps: (1) dissolution of inorganic components (minerals), and (2) digestion of organic component of the bone matrix.