CHAPTER OUTLINE
■ GENERAL FEATURES OF THE SKELETON
The Axial Skeleton
The Appendicular Skeleton
■ BONE STRUCTURE
Composition of Bone
Haversian Systems
Cells of Bone
■ BONE FORMATION
Growth of Long Bones
Bone Remodeling
■ BONE REPAIR
■ JOINTS AND SYNOVIAL FLUID
Blood, Lymph, and Nerve.Supply of Joints
Synovial Membrane
Articular Cartilage
Lubrication of Synovial Joints
Bones are cellular structures in which the extracellular fluid environment of the cell is surrounded by a rigid, calcified frame.
The framework of one bone, when combined with all of the other bones of the body, makes up what is commonly known as the skeleton. The skeleton gives an identifiable form to the body of an animal and provides protection to the cranial, thoracic, abdominal, and pelvic viscera. Also, the medullary cavity of the bones is the principal location of blood formation and the calcified regions act as a sink and a source for many of the needed minerals (cations and anions). Movement of the body parts is enabled by the attachment of muscles to bones. Bones are dynamic structures that are capable of accommodating to different loads and stress by remodeling their shape. Also, function can be restored to broken bones (fractures) by the process of bone repair after appropriate fixation (alignment) of the bone parts.An important aspect of bone study is the movable union between two bones known as a joint. This union is enclosed by a joint capsule. The inner aspect of the joint capsule is lined with a synovial membrane, which produces synovial fluid that provides for lubrication and nutrition of the joint surface.
The physiology of bones, joints, and synovial fluid is important not only because of the association of bones with other body systems but also because bone and joint diseases are frequently encountered in animals.
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