A&P Lect 2 part 3

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A&P Lect 2 part 3
2014-10-03 14:31:47


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  1. where is the spongy bone found in adult long bones?
    at the end of diaphsis 
  2. why does the kidney excrete extra phosphate when calcium levels rise?
    to keep the concentrations in the blood below the solubility product

    kidney stone
  3. difference between total blood calcium and ionized (usable) calcium?
    protein binding
  4. why does a rise in blood pH cause hypocalcemia?
    increases protein binding
  5. why does hypocalcemia produce tetany?
    makes muscle cells easier to depolarize by raising resting membrane potential closer to threshold
  6. anatomy of an osteon?
    • central canal with blood supply
    • lacunae with osteocytes
    • canaliculi with osteocyte connection
  7. 3 types of bone cells?
    osteoblasts- produce new bones

    osteocytes- monitor bone density

    osteoclasts- derived from blood cells, secrete acids, break down bone and release calcium
  8. where are osteoblasts found in adult bone?
    • periosteum
    • endosteum
  9. role of osteoclasts in new bone formation and in fracture healing?
    osteoclasts chew up the cartilage model allowing replacement by new bone 

    ostoeclasts clean up the debris in injuries
  10. what causes bone remodeling?
    new stresses on the bone
  11. what separates primary and secondary ossification centers?
    • epiphysela plates 
    • metaphysis is the cartilage- bone transition
  12. what happens if the kidney excretes extra phosphate and extra calcium?
    the solubility product in the urine is exceeded (kidney stone)
  13. characteristics of the 3 homromes invovled in calcium metabolism?
    • calcitriol- icreases GI abosption of calicum
    • raises blood calicum
    • stimulates osteoclasts

    parathyroid hormone- increases calium blood levesl by increasing kidney reabsoprtion of calcium, increading kdiney production of calcitriol, increasing osteoclast acitivty

    calcitonin- decreases blood calcium by increasing activity of osteoblasts (stimulates new bone formation)
  14. Fractures that occur because of new and repetitive stress on a bone are called _____.
    stress fractures