Bone Biology (Part 1) PDF

Key bone vocabulary: Bone = Osteo Resorption: Osteoclasts Replacement: Osteoblasts Living bone cells: Osteocytes Bone is constantly being remodeled in response to pressure, hormones, diet and other factors. The body stores...

Key bone vocabulary: Bone = Osteo Resorption: Osteoclasts Replacement: Osteoblasts Living bone cells: Osteocytes Bone is constantly being remodeled in response to pressure, hormones, diet and other factors. The body stores calcium in bone, which can be re- absorbed into the blood when blood calcium levels drop. Osteoblasts secrete collagen and elastin fibers that give bones flexibility to bone. These bone forming cells deposit a matrix of minerals that harden when calcium salts are deposited. 1 2 3 Types of Joints (spaces between bones) Fibrous (fibrocartilage) No space or capsule is formed around the joint (and limited movement) E.g., Fibrous fontanelles of skull & sockets of teeth. Cartilaginous joint The articular (joint) surface of each bone is covered with a thin layer of hyaline cartilage Limited movement occurs, such as between vertebrae of the backbone, and for some of the ribs. Vertebrae: Cervical = neck (with transverse foramen (hole on side) Thoracic = mid back (with long spinous process) Lumbar = lower back (large body of disc) 4  Synovial joint These include many of the major joints of the body, knee, hip, shoulder, neck and spine. Each allows specific movement. A dense connective tissue capsule includes cartilage that covers the end bones, and ligaments that stabilize the joint. A synovial membrane on the inner surface of the capsule releases synovial fluid that lubricates the hyaline cartilage on the ends of the bones in a joint. (reduces friction).. Shoulder joint: Coracoid and Acromion (process of scapula) are where ligaments attach (coracoacromial ligament). Supraspinatus muscle slides under these processes and tends to be pinched (impingement injury). Separation at the AC joint (acromion-clavicle). Clavicle, Scapula and Humerus are bones of the Knee joint shoulder joint. Meniscus is a cartilage between femur and tibia. Cruciate ligaments (anterior and posterior) allow for limited twisting of the knee. Collateral ligaments (lateral and medial) help stabilize this Femur, Tibia, Fibula and ‘hinged’ joint. Patella are bones of the knee. 5