Calcium and Parathyroids Flashcards
Why is calcium so important within the body?
- Nerve conduction
- Bone formation
- muscle formation
- Blood coagulation
- Cerebral and cardiac function
- Capillary permeability
- Cell growth and division
- Neurotransmitter action
T/F: The body contains 1-2 kilograms of calcium.
TRUE
Where at is the calcium found in the body and how much in each area?
- Skeleon 98%
- Plasma 0.03%
- ECF 0.1%
- Cells 1 %
T/F: 50% of calcium is Ionized (active form).
TRUE
What are the most important aspects of calcium on the body?
- Heart
- Nervous system,
- Bone formation
Where is the other 50% of the calcium that is non-ionize?
- 41% protein bound (Albumin)
- 9% Combined with anions (DIFFUSIBLE)
How much Ca++ from the bone is readily exchangeable?
0.5%
What will be seen with HYPOcalcemia?
-Nervous System EXCITEMENT \:increased neuronal permeability to Na (easy action potential) \:Tetany \:Seizures \:Chvosteks sign
What will be seen with HYPERcalcemia?
-(Major S/S) Skeletal muscle weaknes
-Nervous system depression
:(Short) QT, (Long) PR,
:constipation
:anorexia
:
What is the treatment for HYPERcalcemia?
- Maintain UOP
- hydrate
- Mithramycin
How much phosphorus is kept within the body?
-1 kilogram
Where at in the body is phosphorus found?
- Skeletal (85%)
- muscle/tissue (15%)
- ECF (1%)
T/F: Phosphorus is easily absorbed in the GI tract.
TRUE
Where are the parathyroids located?
- 4 glands
- Behind the thyroid in the upper and lower poles
What cells makeup the parathyroid?
- chief cells
- oxyphil cells
T/F: The oxyphil cells in the parathyroid release the parathyroid hormone.
FALSE (Chief cells release the parathyroid hormone)
Synthesis and secretion of the _________ hormone is related to calcium _________ in the _____.
parathyroid, concentrations, blood
What will enlarge the parathyroids?
- prolong stimulation
- pregnancy
- lactation
T/F: Decrease in calcium concentration in the extracellular fluid increases the secretion of the PTH.
TRUE
Where does the PTH, cholecalciferol, and Calcitonin work at in the kidneys?
-proximal tubules
What is bone resportion?
The process by which osteoclasts break down bone and release calcium from bone fluid to blood
What is PTH action within the body?
- Increase bone resorption
- Increases reabsorption of Ca++ in the distal tubules
- Decreases reabsorption of phosphate in the renal tubules
- Increases the production of 1,25-dihydroxycholecalciferol
What does 1,25-dihydoxycholecalciferol do?
-Vit. D metabolite which enhances intestinal Ca++ absorption
Increases in PTH in the body results in what?
- Serum: Increased calcium, decreased phosphate
- Urine : Decreased calcium, increased phosphate
T/F: Increases in the excretion of phosphate, potassium, and sodium by increasing the calcium/magnesium/hydrogen reabsorption.
TRUE (Takes place mainly in the distal tubules and collecting ducts)
Where is Calcitonin produced?
-Parafollicular (clear or C cells) of the thyroid
T/F: Calcitonin has the opposite effect of parathyroid hormone.
TRUE
Calcitonin will cause a _________ in the serum calcium/phosphate levels and a ____________ calcium/phosphate excretion.
Decrease, Increase
T/F: Vit D is an active substance for bone deposition and bone absorption.
FALSE (Vit. D must be converted into 1,25-dihydroxycholecalciferol in the LIVER to have any affect on bone depostion or absoption.
What will happen if calcium level drop below normal?
- Tetany
- muscle cramps
- Grand mal seizures
- Cardiovascular collapse
What is the treatment for HYPOparathyroidism?
- PTH
- Intake of calcium and Vit. D (at times 1/25-D3
What does HYPOmagnesemia do?
- cause hypocalcemia resistant to calcium
T/F: Magnesium suppresses the release of PTH.
TRUE
What is Primary HYPERparathyroidism?
-Inappropriate hypersecretion of PTH resulting in hypercalcemia. (DUE TO Hyperplasia, tumor, or pregnancy)
What is Secondary HYPERparathyroidism?
-Hypersecretion of PTH in response to a hypocalcemic streess (Due to Vit. D deficiency and chronic renal disease)
What is Osteomalacia?
-Inadequate mineralization of the bones.
One gram of calcium chloride contains the equivalent amount of ionized calcium as __ grams of Calcium gluconate.
3
Calcium is _________ in cases of magnesium toxicity as may occur in parturients being treated for preeclampsia.
indicated,
Calcium is ____________ in patient with digoxin toxicity as it may cause lethal arrhythmias.
contraindicated
What is Rickets?
Bones fail to mineralize, epiphyses fail to fuse, epiphyseal plates widen, and bowing and fractures occur.
