Calcium Flashcards
Interesting point: how much more concentrated is Ca2+ outside the cell then inside the cell?
10,000x!!!
How much intake of calcium is recommended daily?
1g (1000mg)
What does Vit D do to the apsorption of Ca2+? Phosphorous?
Increases BOTH Ca2+ and PO4-!!!
What is the animal precusor for Vit D? Plant precursor?
anmial:cholecalciferol plant:ergocalciferol
What is the recommendation of daily Vit D intake for the endocrine society?
30ng/ml
What are the two general methods to get Vit D?
Sun exposure and diet
Where is Vit D converted to its 25(OH)D storage form?
The liver
Where is Vit D converted to its active 1,25(OH)2D form?
the KIDNEY!
Can Vit D be made in other tissues beside the kidney?
yep, TB lymphoma leukemia
Where is the Vit D receptor? Membrane or intracellular?
Intracellular
What happens after Vit D has met with its receptor and started the transcription process?
Calcium binding protein gets expressed in the intestine! and Ca2+ absorption increases
What is the relationship between Ca and P absorption once Vit D has done its thing?
they are BOTH absorbed
What are considered the four calcium regulating hormones?
PTH, PTHrP(PTH-related peptide), Calcitonin, 1,25 dihydroxyVitamin D
What controls the minute to minute level of calcium in the blood?
PTH
Where are the PTH receptors?
Bone (get more Ca2+ into blood) and Kidney (reabsorb more Ca2+)
Which G protein pathway does PTH use?
Adenylate Cyclase
What two events occur with PTH stimulation in the kidney?
1.Synthesis of 1,25-VitD 2. Reabsorption of Ca2+
What happens to PO4 when the kidney is stimulated by PTH?
PO4 is EXCRETED while Ca2+ is reabsorbed
Other then a possible malignancy, where do we normally see PTHrP? sorry fellas..
Placenta, amniotic fluid, fetus, breast milk
What is the main action that is different between PTHrP and PTH?
PTHrP does not stimulate activation of Vit D
What do the levels of Ca2+, PO4, and PTH look like after PTHrP is released?
HIGH Ca2+, LOW PO4, LOW PTH
What is the most common cause of PRIMARY hyperparathyroidism? What could a second cause be?
high PTH caused by a single Parathyroid tumor…second cause: hyperplasia of all parathyroid glands
What two substances are most likely produced by a hypercalcemia malignancy?
PTHrP and 1,25 Vit D
What is the disease of “ooones”?
hypercalcemia: stones, groans, moans, overtones, bones
What are PTH levels with high PTHrP in urine and high Vit D in urine?
Both conditions will show low PTH (c/o feedback)
What blood serum Ca2+ level would you recommend surgery for hypercalcemia?
greater or equal to 11 mg/dl (you even do surgery if no symptoms!!!!)
Would you recommend surgery to a hypercalcemia to a younger or older pt?
younger sub 50
What are three possible causes of hypocalcemia?
low PTH, Low Vit D, Low Ca2+ intake
What condition are we talking bout with muscle spasms , tetany, tingling around mouth/fingertips
hypocalcemia
What does hypoparathyroidism do for Ca, Phos, and Vit D levels?
low ca, high phos, low vit d
What is the main outcome of childhood Vit D deficiency?
rickets!
What does low Vit D do to Ca, phos, and PTH levels?
low Ca, low phos, high PTH
What does Vit D deficiency do to bone?
Makes it weak. Sacrifice bone Ca2+ to increase blood Ca2+ (c/o high PTH)
What is the main adult Vit D deficiency outcome? What is the main symptom of this deficiency?
oseteomalacia..bone pain!
HypoCa levels of phos, 1,25 Vit D, PTH…
phos high, 1,25 Vit d low, PTH Low
HypoCa levels of phos, 1,25 Vit D, PTH…
phos low, 1,25Vit D low, PTH high
HypoCa levels of phos, 1,25 VitD, PTH…
phos high, 1,25Vit D low, PTH High
What is blood Ca with primary hyperparathy?
high Ca
What is blood Ca with secondary hyperparathy?
low ca (then causes high PTH)
