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34 Cards in this Set
- Front
- Back
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What does osteo mean?
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Bone (from Greek)
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What are the three main types of bone cells?
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1. Osteoblasts
2. Osteoclasts 3. Osteocytes |
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What type of collagen do osteoblasts produce?
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type 1 collagen
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What do osteoblasts promote?
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the deposition of Ca salts on the osteoid
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What do osteoblasts secrete?
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alkaline phosphatase
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What do osteoblasts have receptors for?
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1. PTH
2. estrogen 3. progesterone |
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What do osteoblasts differentiate into?
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osteocytes
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What is an osteocyte?
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a mature, terminally differentiated cell
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Where are osteocytes?
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in the lacunae and canaliculi of the matrix (spider-like shape)
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How are osteocytes linked to each other?
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by gap junctions
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How do osteocytes maintain the ECM?
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Recycle Ca salts
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What is an osteoclast?
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A giant, motile, multinucleated cell
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What are osteoclasts derived from?
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Monocytes
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Where are osteoclasts located?
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In resorption (Howship's) cavities
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What regulates osteoclasts?
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Calcitonin
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What is a ruffled border?
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The border of an osteoclast that secretes proteolytic & lysosomal enzymes
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What happens to bone in osteoporosis?
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There is more bone resorption, therefore more osteoclast activity (remove Ca salts)
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What two main categories make up the bone matrix?
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1. organic: 20-30%
2. inorganic: 70-80% |
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What is in the organic part of the bone matrix?
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1. type 1 collagen
2. glycoproteins |
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What is in the inorganic part of the bone matrix?
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hydroxyapatite
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Which part of the matrix contributes to the strength/resilience?
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The organic part (type 1 collagen, glycoproteins)
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Which part of the matrix contributes to hardness/rigidity?
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The inorganic part (hydroxyapatite)
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What is the type of bone cell that I have not covered yet?
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Osteoprogenitor (Osteogenic) cells
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What are osteoprogenitor cells?
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Pleuripotential mesenchymal stem cells
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What type of cell do osteoprogenitor cells differentiate into?
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Osteoblasts
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Where are osteoprogenitor cells?
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"bone lining cells"
- activated in the adult in fracture repair |
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What is the most ubiquitous protein in the body?
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Collagen (30%)
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What does collagen consist of?
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Polypeptide alpha chains
1. glycine (33%) 2. proline (12%) 3. hydroxyproline (10%) |
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What does "great tensile strength" of collagen mean?
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Resists stretching while retaining flexibility
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Which type of collagen is most abundant?
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Type I
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What are some representative tissues containing collagen type I?
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skin, tendon, bone, dentin
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What are some representative tissues containing collagen type II?
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cartilage, vitreous body
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Which collagen has it's main role as "resistance to tension"?
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type I
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Which collagen has it's main role as "resistance to pressure"?
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type II
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