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23 Cards in this Set
- Front
- Back
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What are the 3 hormonal control for calcium.
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PTH
Vitamin D Calcitonin |
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What are the 3 major pools of CALCIUM in the body?
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intracellular calcium
calcium in ECF and blood bone calcium |
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low pH (acidosis) causes
? Ca2+ solubility ? free Ca2+ |
INCREASE in Ca2+ solubility
INCREASE in free Ca2+ |
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high pH (alkalosis) causes
? CaPO4 ? free Ca2+ |
INCREASE in CaPO4
DECREASE free Ca2+ |
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an INCREASE in [PO4]
will cause ? |
decrease FREE CALCIUM
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Active absorption of Calcium in the duodenum is stimulated by ?
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1,25-(OH)2-D
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excreted phosphate is REABSORBED back into the renal ?
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renal PROXIMAL tubules
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? bone is more important for Ca turnover due to the larger total surface area and greater accessibility.
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Trabecular Bone
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Bone development begins with formation of ? (a collagen matrix secreted by osteoblasts)
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OSTEOID
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The formation of Hydroxyapatite requires what 5 things?
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Ca
PO4 Vitamin D PTH osteoblastic proteins (alakaline phosphatase, osteocalcin, osteopontin, osteonectin) |
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? and ? are used as markers of osteoblast activity.
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Alkaline Phosphatase
Osteocalcin |
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Canaliculis in the bone profide a huge inerface between the mineralized bone and intercellular fluid.
it also permits ? with transfer of Ca and PO4 to the exterior via ? connecting interior and surface osteocytes. |
Osteocytic Osteolysis
via syncytial process |
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What is Osteocytic Osteolysis?
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increased PTH
=> increases Ca2+ permeability in osteocytes/osteoblast => Ca2+ from osteoid goes into OSTEOCYTE => transferred to OSTEOBLAST via GAP JUNCTIONS => secreted into ECF |
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What is the responsible cell for BONE RESORPTION?
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Osteoclast
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Osteoblastic fators that regulate differentiation and activation of osteoclasts are ?
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RANK ligand
IL-6 M-CSF (macrophage colony stimulating factor) Osteoprotegerin (OPG) |
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What form of Vitamin D is hydroxylated in the liver and transported to the kidney?
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Vitamin D (CHOLECALCIFEROL)
-->25 HYDROXYLASE (liver) --> 25 OH-D (liver transported to kidney) => 1 HYDROXYLASE ---> 1,25 (OH)2-D active OR => 24 HYDROXYLASE --> 24,25 (OH)2 -D inactive |
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what is the active form of Vitamin D called?
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1,25 (OH)2 -D
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all forms of VITAMIN D are bound to?
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α-globulin
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What are the 3 nuclear receptor effects of 1,25 (OH)2 -D ?
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DUODENUM
--> increases synthesis of Ca2+ pump , CALBINDIN, and Ca2+ channel --> stimulates phosphate absorption BONE -->stimulates Ca2+ and PO4 resorption -->provides Ca and PO4 from old bone to mineralize new bone Kidney -->targets on DISTAL TUBULE and enhances Ca and PO4 reabsorption |
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? is a CALCIUM-BINDING protein that rises hours after Ca entry from intestinal lumen. Helps ferry Ca across the intestinal cell and buffer the high Ca2+ concentration
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CALBINDINS
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Chronic Hypomagnesium inhibits ?
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PTH synthesis
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When PO4 levels INCREASE
this causes Ca2+ to? => PTH ? |
Ca2+ DECREASE
=> PTH INCREASE |
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PTH effects are mediated through what type of secondary mechanism?
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cAMP mechanism
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