MICROANATOMY

Detailed explanation-1: -Osteoblasts in the periosteum form compact bone around the external bone surface. At the same time, osteoclasts in the endosteum break down bone on the internal bone surface, around the medullary cavity.

Detailed explanation-2: -Blood vessels invade the cavities, and osteoblasts and osteoclasts modify the calcified cartilage matrix into spongy bone. Osteoclasts then break down some of the spongy bone to create a marrow, or medullary, cavity in the center of the diaphysis.

Detailed explanation-3: -Osteoclasts are the cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity.

Detailed explanation-4: -During bone resorption, the osteoclasts resorb the bone surface forming depressions known as Howship’s lacunae. Resorbing osteoclasts are highly polarized cells containing four structurally and functionally distinct membrane domains.

Detailed explanation-5: -Osteoclasts are the cells responsible for bone resorption. Located on bone surfaces, osteoclasts are large cells with as many as 50 nuclei. They secrete acids and hydrolytic enzymes that dissolve the bone matrix.