my exam 3 notes - EXAM 3 NOTES I Skeletal System All bones...

This preview shows page 1 - 3 out of 21 pages.

EXAM 3 NOTES I. Skeletal System: All bones of the body plus articulations A. Bone Tissue: (Specialized Connective Tissue) 1. Components a) Mature Cells (Osteocytes) (1) Begin as Osteoblasts; Osteoblasts make intercellular substance; Result: Cells in Lacunae (Spaces) surrounded by intercellular substance and now are called Osteocytes b) Intercellular Substance (1) Fibers: Collagen that are Embedded in the Organic Matrix (2) Matrix: Solid Material Outside Lacunae (a) Organic (Osteoid): Made of High Concentrations of Gly- coproteins and Proteoglycans (b) Inorganic: Made of Hydroxyapatite Crystals [Ca 3 (PO 4 ) 2 and Ca(OH) 2 ] Crystals Form on Collagen Fibers; and Accumulate on Fibers in Osteoid Making Bone a Hard Tissue B. Structural Types of Bone (Based on Orientation of Lamellae) 1. Spongy, Cancellous or Trabecular Bone a) Trabeculae (Flat Slightly Curved Plates of Bone Tissue) (1) Few Linear Slightly Curved Lamellae (Layers of Hard Tissue) Make up a Trabeculum (2) Spaces Inside Walls Formed byTrabeculae are Filled with Red Bone Marrow 2. Compact or Cortical Bone (of Long Bone) a) Several Lamellae Present in Concentric Circles 3. Comparison of Spongy and Compact Bone a) Spongy Bone Lamellae: Present in Linear, Curved Layers that Form Tra- beculae b) Compact Bone Lamellae in Concentric Circles C. Microscopic Structure of Compact Bone Osteon or the Haversian System 1. Haversian Canal: Oriented Vertically in Center of Osteon; space that con- tains: Blood vessels, Lymph Vessels and Nerve fibers 2. Lamellae: Concentric Layers of Hard Bony Matrix Surrounding Haversian Canal; Alternate with 3. Lacunae: Layers of Spaces Containing Osteocytes in Concentric Circles 4. Cannaliculi: Fine Canals that Cross Lamellae; Interconnect Lacunae in Different Layers Canaliculi in First Lamella Connect to Haversian Canal: Can- aliculi Carry ECF from Blood Capillaries in Haversian Canal to all Lacunae in a Haversian System 5. Volkmann's Canals: Oriented Horizontally; Interconnect Haversian Canals to Each Other a) Transmit Blood Vessels from Periosteum (Located at Outer Surface of a Bone) into Compact Bone and Terminates at the Endosteum (Membrane Lin- ing Central Bone Marrow Cavity of Long Bones) 6. Outer Circumferential Lamellae: Located at Outer Surface of Compact Bone Under the Periosteum 7. Interstitial Lamellae (not illustrated) Located Between Osteons
EXAM 3 NOTES 8. Inner Circumferential Lamellae (Not illustrated) located around border of bone marrow cavity D. Classification of Bones (Based on shape) 1. Long Bones: Length greater than width a) Bones of Extremities: humerus, radius, ulna, metacarpals, femur, tibia, fibula, metatarsals and phalanges 2. Short Bones: No difference in length or width carpals and tarsals except calcaneus (irregular) 3. Flat Bones: Two parallel thin plates of compact bone separated by spongy bone a) Most Skull Bones: occipital, parietal, frontal, zygomatic nasal and lacrimal bones: ribs, scapula and sternum 4. Irregular Bones: Usually shaped vertebra, sacrum, temporal, mandible, maxilla, ethmoid, sphenoid, pelvic and coccyx 5. Sesamoid Bones:

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture