z- minerals and bone metabolism (ch-38) Flashcard

Calcium Functions
Calmodulin (made up of 4 Ca2+ ions) – it activates adenylate cyclase and phosphodiesterase
Calcium binds to a protein to form Troponin – found in cardiac muscle
Cell communication
Controls endocrine gland secretion
Needed for blood coagulation
(made up of 4 Ca2+ ions) – it activates adenylate cyclase and phosphodiesterase
Phosphate Function
Part of the cell membrane structure
Gene Replication
Regulation of Calcium & Phosphate
Parathyroid Hormone
Vitamin D
Opposite of PTH
Produced by C-cell of PT gland
Net effect:
v Ca2+
^ Phosphate
Hypercalcemia: stimulates release
Hypocalcemia: inhibits release
Vitamin D
Stimulates membrane transport of Ca2+ b/t cells
Primary Hyperparathyroidism
leads to hypercalcemia/hypophosphatemia > hypercalciuria > urolithiasis/nephrocalcinosis (kidney stones)
rare, genetic
Leads to renal osteodystrophy (ROD)
No renal excretion of phosphate
rare, genetic, X-linked
Defect in renal absorption of phosphate
^ excretion of phosphate in urine
deficency in PTH caused by infection or parathyroidectomy
PTH level is normal or high means that there is a receptor problem
Effect of Hypercalcemia on Calcitronin
stimulates release
Effect of Hypocalcemia on Calcitronin
inhibits release
EDTA and Calcium
cannot use because of chelation
Heparin and Calcium
no interference
Citrate/Lactate and Calcium
can bind to free calcium to make ligands
falsely decreased result for an ionized calcium test
they are ok for total calcium tests
favors disassociation of Ca2+ from ligands and proteins
favor association of Ca2+ from free Ca2+ to proteins and ligands
Calcium and Protein
form Troponin – found in cardiac muscle
Regulation of Calcium & Phosphate
Total Calcium

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