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Anatomy and Physiology of Dogs and Cats. Bones, Joints, Synovial Fluid (Part Two). Periosteum. Composed of an outer fibrous layer and an inner cell-rich layer containing osteoblasts or other cells that can become osteoblasts. Periosteum. Functions Increase diameter of bone Heals fractures.
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Anatomy and Physiology of Dogs and Cats Bones, Joints, Synovial Fluid (Part Two)
Periosteum • Composed of an outer fibrous layer and an inner cell-rich layer containing osteoblasts or other cells that can become osteoblasts
Periosteum • Functions • Increase diameter of bone • Heals fractures
Haversian System/Osteon • Unit of structure for compact bone • Central haversian canal surrounded by concentric layers of bone (lamellae) • Lack spongy bone • Contain blood vessels, connective tissues, nerve fibers and lymphatic vessels
Cells • Osteoblasts • Produces collagen for the initial unmineralized bone and then helps calcify the bone matrix
Cells • Osteocyte • Mature bone cell • Maintains the bone matrix • Can synthesize and resorb matrix to an extent
Cells • Osteoclasts • Large, motile, multinucleated • Resorb bone for remodeling https://www.youtube.com/watch?v=78RBpWSOl08
Joints and Synovial Fluid • Synovial joints are those that allow one surface to glide over the other • Motion is facilitated by articular cartilage and synovial joint fluid contained in joint capsule • The meniscus within joint capsule serves as a cushioning function
Synovial Fluid • Contains hyaluronic acid and lubricin (glycoprotein) • Secreted by synovial membrane • Lubricates articular surfaces (light vs heavy loads)
Blood and Lymph Supply to Synovial Joints • Arteries enter the bone near the line of the capsule attachment and form a network around the joint • Capillaries deliver nutrients • Lymph vessels present in blood vessels • Lymph vessels that leave joint, drain into regional lymph nodes
Nerve Supply and Synovial Joints • Functions: • Pain and reflex • Role in posture, locomotion, and sense of tension from motion (tendons, muscles)