BMS 100 - Chapter 7 Outline

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Bone Structure (p. 126)

1. Parts of a long bone (humerus, femur, etc.)
   1. epiphyses = enlargements at each end of bone; are largely covered by articular cartilage
   2. diaphysis = the "shaft" of the bone; is largely covered by a periosteum (membrane)
      • outer layer of periosteum: for attachment of tendons & ligaments
      • inner layer of periosteum: can produce new tissue for bone "thickening"
   
   
2. Synovial joints (allows free movement of bones)
   • include a joint cavity between the bones and a joint capsule that surrounds the joint
     • outer layer contains many collagen fibers (tough but flexible) - holds bones together
     • inner lining = synovial membrane, which secretes synovial fluid
     • What is the consistency of synovial fluid? What is its function?
   
   
3. Bone tissue
   1. Compact bone tissue (dense, protective)
   2. Spongy bone tissue - is hard but has large spaces (reduces weight of bone).
      • Red bone marrow (is soft)
        • located within spongy bone tissue of certain bones
        • capable of producing all types of blood cells
   3. Layers of a long bone, from outside in: periosteum > compact bone tissue > spongy bone tissue > cavity
   4. Bone tissue is a type of connective tissue.
   5. All connective tissues consist of 1) cells and 2) matrix (outside of cells).
   6. The matrix consists of fibers and ground substance.
   7. Ground substance
      • mainly calcium phosphate, which is hard
      • When blood calcium is low, cells called "osteoclasts" break down bone matrix, releasing calcium ions which can enter blood.
   8. Collagen fibers - contribute to overall "flexibility" (resilience) of bone
   9. How the matrix is produced:
      1. cells called osteoblasts secrete "osteoid" (semisolid, contains protein)
      2. osteoblasts then secrete calcium salts
      3. matrix solidifies
      4. osteoblasts are entrapped and become "osteocytes."

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Bone Development and Growth (p. 127)

1. Intramembranous bones – includes mainly the "flat bones" of the skull.
   1. Microscopic ossification centers (with osteoblasts) appear within soft tissue.
   2. Osteoblasts produce bone tissue
   3. At outer edge of oss. center:
      • more osteoblasts are produced
      • osteoblasts add bone tissue to edge
      • the area of bone tissue continuously expands outward
2. Endochondral bones - includes "long bones" of limbs and other bones
   1. Endochondral bones develop from cartilage “models.”
   2. Primary ossification center:
      • appears in center of future diaphysis (central shaft)
      • ossification proceeds out from primary oss. center
   3. Later, secondary ossification centers appear and begin converting epiphyses (ends) from cartilage to bone.
   4. During childhood/adolescence, epiphyseal plates remain between the diaphysis and the epiphyses.
   5. The epiphyseal plates ("growth plates") are responsible for bone lengthening.
      • zone of proliferating cartilage - produces new cells/tissue
      • zone of ossification - tissue turns to bone and adds to diaphysis (diaphysis grows longer)
      • The zone of proliferating cartilage eventually "shuts down."

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Chapter 7 Study Questions at OLC – 2, 3, 5, 6, 7, 10, 13, 14, 29, 30, 31, 32, 33, 34, 36, 37

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Spring 2011