Larger osteoclasts resorbing bone at higher rate Newly deposited bone poorly

Larger osteoclasts resorbing bone at higher rate

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Larger osteoclasts resorbing bone at higher rate Newly deposited bone poorly formed Most commonly affected bones: pelvis, skull, vertebrae, femur, tibia Symptoms of bone deformity and pain Compact and Spongy Bone Microscopic Anatomy Figure 7.8a-b Compact bone composed of osteons - Small cylindrical structures Also known as Haversian systems Basic functional and structural unit of mature compact bone Oriented parallel to bone diaphysis In cross section appears like bull’s-eye target Components of osteons of compact bone Figure 7.7a - b
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Central canal - cylindrical channel lies at center of osteon and runs parallel to it blood vessels and nerves traveling here Concentric lamellae - rings of bone connective tissue surround the central canal contain collagen fibers oriented at an angle 90 degrees from previous and next lamellae give bone part of its strength and resilience Osteocytes - mature bone cells found in small spaces between concentric lamellae ( lacunae ) maintain bone matrix Canaliculi - tiny interconnecting channels within bone connective tissue extend from each lacuna travel through lamellae connect to other lacunae and central canal house osteocyte projections permitting intercellular contact allow travel of nutrients, minerals, gases, and wastes between blood vessels and osteocytes Other components of compact bone Perforating canals ( Volkmann canals ) - contain blood vessels and nerves run perpendicular to the central canals help connect multiple central canals within different osteons Circumferential lamellae - rings of bone run the entire circumference of bone Interstitial lamellae - components of compact bone between osteons may be partially resorbed osteons look like a “bite” taken out of them Components of spongy bone Figure 7.7c Trabeculae - open lattice of narrow rods and plates of bones bone marrow filling spaces between form a meshwork of crisscrossing bars provide great resistance to stresses Structure of hyaline cartilage Population of cells scattered through matrix of protein fibers Embedded in a gel-like ground substance includes proteoglycans but not calcium Resilient and flexible High percentage of water Highly compressible and a good shock absorber Avascular and contains no nerves Chondroblasts - produce cartilage matrix Chondrocytes - chondroblasts that have become encased within the matrix occupy small spaces called lacunae maintain the matrix Perichondrium - dense irregular connective tissue covers cartilage and helps maintain its shape Comparison of Bone Connective Tissue & Hyaline Cartilage Connective Tissue (Table 7.1) Cartilage Growth Process of cartilage growth Begins during embryologic development Growth in length through interstitial growth occurs within the internal regions of cartilage Growth in width by appositional growth occurs on cartilage’s outside edge
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Steps of interstitial growth Figure 7.9a 1) A chondrocyte within a lacuna is stimulated to mitotically divide.
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