Renal-Chapter 31 Calcium Flashcards
Ca2+ ECF levels too low
-effect
Hypocalcemia
Can change muscle and nerves excitability
Extreme=Hypocalcemic tetany
Ca2+ ECF levels too high
-effect
Hypercalcemia
Depresses neuromuscular excitability
Extreme=Cardiac arrhythmias
How does PTH regulates plasma concentration?
Stimulates bone resorption to release Ca2+
Increas activation of vitamin D to increase intestinal reabsorption of Ca2+
Increase renal tubular reasborption of Ca2+
T/F Ca2+ is excreted, filtered, secreted, and reasborbed, by the kidneys
F
Ca2+ is not secreted by kidney tubules
T/F Most PCT reabsorption is paracellular. Why?
T
20 percent is transcellular…uses E and 3Na:1Ca2+
What sections of nephron are sensitive to PTH
-What type of transport
LOH and DT
LOH=passive via paracellular
DT= active transport
Explain the regulation of tubular calcium reabsorption
PTH will increase reabsorption of Ca2+ in LOH and DT
There will be increase phosphate concentration
Increase reabsorption by kidney
DT reabsorption is stimulated by metabolic alkalosis and inhibited by acidosis.
If there is a decrease in Ca2+ excretion, what will you see? PTH ECF BP PO4 Alkalosis or acidosis
Increase PTH
Increase ECF
Decrease BP
Increase PO4
Alkalosis
If there is an increase in Ca2+ excretion, what will you see? PTH ECF BP PO4 Alkalosis or acidosis
Decrease PH
Decrease ECF
Increase BP
Decrease PO4
Acidosis
How is renal phosphate excretion regulated?
Overflow mechanism
Mg excretion is increased by?
Increased ECF Mg
EC volume expansion
Increased ECF Ca2+
