5 bones 118 - Osteoclasts are large, multinucleated cells...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Biology 118 5. SKELETONS Skeletons provide support, protection and leverage, a mineral reserve, and produce blood cells. BONE STRUCTURE: Bones are made up of a tough matrix of extracellular protein, like collagen, and calcium salts, particularly calcium phosphate. Bones have their own blood supply. These blood vessels run through channels in the bone. Osteocytes embedded within the bone are able to exchange materials with the blood vessels by means of tiny canals in the matrix, which connect the cells to the channels containing blood vessels. Bone cells are present within the tough matrix of bone, in little cavities called lacunae. Osteocytes maintain normal bone structure and assist in repairs.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Osteoclasts are large, multinucleated cells that break down the bone matrix and mobilize the calcium salts stored in bone. Osteoblasts produce new matrix, depositing calcium salts into new bone matrix. These cells become osteocytes once they are fully surrounded by bone matrix. HOMEOSTATIC MECHANISMS: Remodeling osteocytes are always active, building up and tearing down bone matrix. This serves to slowly replace bone material over time, and to respond to the stresses of exercise. Bones act as a reservoir of calcium, an ion crucial to several cellular processes. The concentration of calcium in body fuids is closely regulated by hormones like calcitonin and parathyroid hormone....
View Full Document

Ask a homework question - tutors are online