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118 terms

A7: Evaluating Mineral Balance

STUDY
PLAY
Where is calcium found in the body
99% of body calcium is stored in bone and 1% is found in soft tissues and body fluids
Besides bone and teeth formation what are some other functions of calcium in the body (5)
1. Coagulation 2. Enzyme activation 3. Transmission of nerve impulses 4. Decreasing cell membrane and capillary permeability 5. Muscle contraction
Blood levels of calcium are regulated by the interaction of what three things
1. PTH 2. Calcitonin 3. Activated Vitamin D
Dietary calcium is absorbed from the small intestine into the bloodstream. What does the amount absorbed depend on (3)
1. Body`s calcium needs 2. Form and amount of dietary calcium 3. Presence of vitamin D
Calcium that is not absorbed by the small intestineis excreted in the ____ Excess calcium in the serum is excreted in the ______
-in the feces -in the urine
Almost all the calcium in the blood is located in the ______
plasma
In what two forms is plasma and serum calcium found
1. Non-diffusible protein bound 2. Diffusible non-protein bound
Non diffusible protein bound calcium is approximately ____% of serum calcium. Is not filtered by the ______. Most of it is bound to _____ (___%), and ___% is bound to ________
-40% -Glomerulus -Albumin -32% -8% -alpha and beta globulins
Diffusible non-protein bound calcium is complexed with ____ and _____ (about __%). 50 % of it is ______
-Citrate -Phosphate -10% -Ionized
The proportion of ionized calcium is affected by the ____ of the blood. What kind of calcium is this
-pH -Diffusible non-protein bound
Alkalosis _______ the ionized calcium level and acidosis ________ the ionized calcium level
-decreases -increases
In _________ the protein-bound fraction and total serum calcium is _______ but the ionized calcium level is _______. Therefore a correction formula is applied to the measured serum to assess the true calcium level
-Hypoalbuminemia -decreased -normal
In hypoalbuminemia what do we have to do to get a true serum calcium level and why
-We have to apply a correction formula to the measured serum because the protein bound fraction in hypoalbuminemia is decreased but the ionized level is increased
T or F For calcium determination we dont have to collect samples in a fasted state
F
_____ and _______ cannot be used as an anticoagulant because they act by _______ ________. In both cases the level of calcium in plasma would be falsely _____
-Oxalate and EDTA -Chelating calcium -low
In calcium determinations serum or plasma must be separated from the cells as soon as possible, why
-Because calcium may diffuse into the cells resulting in decreased values
______ results in a slight decrease in calcium in plasma, why?
Because of the ruptured erythrocytes dilute the plasma
What is the most common test used to measure calcium
Total calcium (bound and unbound)
The ionized fraction of calcium can also be measursed but is usually only requested when
The total calcium level is outside the reference range
Calcium and _______ have an inverse relationship
Phosphorous
Dissolution or degeneration in bone tissue disease is termed
Osteolytic
List six conditions that result in hypercalcemia
1. Dehydration 2. Osteolyic Bone Lesions 3. Hypoadrenocorticism 4. Primary hyperparathyroidism 5. Pseudohyperparathyroidism 6. Vitamin D toxicity
Over supplementation of vitamin D can cause
hypercalcemia
Why does hyperparathyroidism cause hypercalcemia?
Because neoplasia of the parathyroid glands causes the production of PTH which increases serum calcium levels
Why does hypoadrenocorticism result in hypercalcemia?
An increased renal tubular reabsorbtion of calcium
Why does dehydration result in hypercalemia?
It raises serum albumin giving the impression of hypercalcemia
Why do osteolytic bone lesions cause hypercalcemia?
Calcium is released from bone as it is destroyed
Name eight conditions that can result in hypercalcemia
1. Hypoalbuinemia 2. Acute Pancreatitis 3. Primary Hypoparathyroidism 4. Nutritional Secondary Hyperparathyroidism 5. Renal Failure 6. Parturient Paresis (milk fever, eclampsia) 7. Hypomagnesemic Tetany in Ruminants 8. Antifreeze Poisoning
Where is the body's phosphorus found?
80% in the skeleton and 20% in the soft tissues and body fluids
What are four functions of phosphorus? (other than being a component of bones and teeth)
1. Structural component of RNA and DNA 2. Important component of cell membranes (phospholipids) 3. Important component of high energy phosphate compounds (ATP and creatine phosphate) 4. Important role in carbohydtrate metabolism and many metabolic pathways (glucose, amino acid and protein formation; fatty acid transport)
Dietary phosphorus is absorbed from the small intestine in the presence of ______ ____ _
Activated Vitamin D
Excess dietary phosphorous is excreted in the ____
feces
How does PTH affect phosphorus?
It decreases the reabsorption of phosphorus in the kidney tubule resulting in phosphaturia
The _____ and ______ regulate the serum level of phosphorus through the actions of ___ and vitamin ____
-intestine and kidney -Vitamin D and PTH
Phosphorus is present in blood in what two forms?
1. Inorganic phosphate in serum and plasma 2. Organic form in RBCs (Majority)
Why does acute pancreatitis cause hypocalcemia?
Because of the formation of calcium deposits in digested mesenteric fat
Why does hypocalcemia occur in antifreeze poisoning?
Because calcium oxalate crystals form in the renal tubules
Tests that measure serum phophorus levels measure the _____ form of serum or plasma phosphorous
inorganic
When assessing serum phosphate levels serum or plasma should be separated asap from the cells to prevent ______ of _______ phosphate to the ________ form causing falsely _____ results
-hydrolysis -organic -inorganic -high
When assessing serum phosphate values _____ and _____ may increase values
hemolysis and lipemia
List five things that result in hyperphosphatemia
1. Renal Insufficiency or failure 2. Hyperthyroidism 3. Hypoparathyroidism 4. Nutritional Secondary Hyperparathyroidism 5. Vitamin D Toxicosis
Is Hypophosphatemia a common or uncommon laboratory finding?
Uncommon.
List three conditions that can result in significant hypophosphatemia
1. Primary hyperparathyroidism and pseudohyperparathyroidism 2. Parturient Paresis 3. Nutritional Secondary Hyperparathyroidism
T or F Mildly lowered serum phosphorous without hypercalcemia is usually a significant finding
F It is insignificant
What is parturient paresis? What two conditions can it result in?
-Milk fever in cattle that is the result of an increased demand for nutrients for lactation resulting in deficits 1. Hypophosphatemia 2. Hypocalcemia
Where is magnesium found in the body?
75% in skeleton (complexed with calcium and phosphorous) and 25% in soft tissues and body fluids
WHat is the second highest concentration of intracellular cation is ______ (the first is _____)
-Magnesium -Potassium
WHat is the main function of intracellular magnesium?
As an enzyme activator, especially reactions involving the transfer of a phosphate group (like alkaline phosphatase)
What is the main function of extracellular magnesium?
Plays a role of impulse transmission at neuromusclular junctions
Increased extracellular magnesium levels _____ neuromuscular excitability whereas decreased levels produce ______ excitability and _____. Since ______ also affects nerve transmission there is some evidence of a reciprocal relationship between it and magnesium
-depress -increased -tetany -calcium
What are the two forms of plasma magnesium?
1. Diffusible form (non-protein bound) 2. Non-diffusible form (protein bound)
Dietary magnesium is absorbed into the bloodstream by the small intestine. Is this influenced by vitamin D? How is excess dietary Mg excreted?
-No -In the feces
Excess plasma magnesium is excreted in the _____.
urine
Urinary reabsorption of magnesium is influenced by what four things?
1. Physiological factors 2. Metabolic factors 3. Drugs 4. Disease states
T or F Magnesium is directly affected by PTH and Vitamin D
F
When assessing magnesium is serum or plasma used? What colored top?
-Either -Green
What does the test for measuring serum Mg actually measure?
Total Mg (bound and unbound)
What three things cause falsely decreased results for total Mg?
Chelating anticoagulants 1. Oxalate 2. Citrate 3. EDTA
What will cause falsely increased results in total Mg?
Hemolysis
What is a more common laboratory finding, Hypermagnesia or Hypomagnesia? What is the cause?
-Hypermagnesia - Declining GFR results in decreased filtration and excretion of magnesium increasing its levels
What is hypomagnesia most often caused by? In what animals?
-Hypomagnesemic Tetany -Cattle and sheep (Grass tetany)
What are the symptoms of Hypomagnesemic (Grass) Tetany (4)?
1. Twitching of muscles 2. Staggering 3. Restlessness 4. Increased sensitivity to noise
In adult cattle grass tetany occurs due to inadequate magnesium content in the grass they are feeding on. The Mg content is low in the ____ and increases in the ______. The treatment is ______ ________
-Spring -Summer -Intravenous magnesium
Nutritional Secondary Hyperparathyroidism can cause what regarding serum calcium and phosphorous
-Hypocalcemia -Hypophosphatemia (later) or Hyperphosphatemia(early) (depending on the stage of the nutritional imbalance)
What does Vitamin D toxicity cause in regards to serum calcium and phosphorous levels?
-Hypercalcemia -Hyperphosphatemia
What does hypoparathyroidism cause in regards to serum calcium and phosphorous levels?
-Hypocalcemia -Hyperphosphatemia
When levels of PTH are decreased how are the calcium and phosphorous levels affected?
-Low calcium and high phosphorus serum levels occur (hypocalcemia and hyperphosphatemia)
____% of hypomagnesemic tetany cases in ruminants (grass tetany) are also hypocalcemic
75%
How does hyperparathyroidism cause changes in serum levels of calcium, phosphorus and magnesium?
1. Hypercalcemia (PTH increases serum Ca) 2. In secondary nuritional hyperparathyroidism hyperphosphatemia occurs at first -In primary hyperparathyroidism a hypophosphatemia occurs -3. Magnesium isn't affected by PTH
How does renal insufficiently or failure change serum levels of calcium, phosphorus or magnesium?
1. Hypocalcemia (decreased renal production of vitamin D equals decreased calcium) 2. Hyperphosphatemia (kidney unable to excrete) 3. Hypermagnesemia (declining GFR decreased excretion)
Which is involved in preservation of skeletal structure, Ca, P or Mg? (can be more than one)
All three
Which is involved in activation of enzymes, Ca, P or Mg? (can be more than one)
Ca and Mg
Which is associated with high energy bonds, Ca, P or Mg? (can be more than one)
Phosphorus
Which is involved in transmission of nerve impulses, Ca, P or Mg? (can be more than one)
Ca and Mg
Which is involved in blood coagulation, Ca, P or Mg? (can be more than one)
Ca
Which is 99% complexed with skeleton and teeth, Ca, P or Mg? (can be more than one)
Calcium
Which is 15 - 20% located in soft tissue and body fluids, Ca, P or Mg? (can be more than one)
Phosphorus
Which has it's intestinal absorption increased by vitamin D, Ca, P or Mg? (can be more than one)
Ca and Phosphorus
Which when there are excess plasma levels will result in mineral excretion in urine, Ca, P or Mg? (can be more than one)
Ca, P and Mg
Which's blood level is directly influenced by PTH, Ca, P or Mg? (can be more than one)
Ca and P
Which will have increased levels as a result of hyperparathyroidism, Ca, P or Mg? (can be more than one)
Calcium
Which will have decreased levels during renal failure, Ca, P or Mg? (can be more than one)
Calcium
Which will have decreased levels as a result of parturient paresis, Ca, P or Mg?
Ca and P
Which is 75% found in skeleton and teeth, Ca, P or Mg?
Magnesium
Which of the following have a reciprocal relationship, Ca, P or Mg?
Calcium and Magnesium
Which will have decreased levels in primary hyperparathyroidism, Ca, P or Mg?
Phosphorus
Which will have decreased levels causing tetany, Ca, P or Mg?
Calcium and Mg
Which is involved in muscle contraction, Ca, P or Mg?
Ca
Which is important in carbohydrate metabolism, Ca, P or Mg?
P
Which has increased levels in renal failure, Ca, P or Mg?
P and Mg
Describe two effects PTH has on calcium levels
1. Mobilizes calcium from bone, therefore increases calcium in blood 2. Increases calcium reabsorption from kidney tubule into blood
What main body functions would Total Protein test evaluate? (3)
(Albumin) 1. Dehydration 2. Renal function 3. Hepatic function
What main body functions does albumin tests evaluate? (3)
(Albumin) 1. Dehydration 2. Renal function 3. Hepatic function
What main body functions does calcium tests evaluate? (2)
1. Mineral balance 2. Renal function
What main body functions does phosphorus tests evaluate? (2)
1. Mineral balance 2. Renal function
What main body functions does BUN evaluate? (2)
1. Renal function 2. Dehydration
What main body functions does creatinine evaluate? (2)
1. Renal function 2. Dehydration
What main body functions does total bilirubin evaluate? (2)
Liver 1. Damage 2. Function
What main body functions does Alkaline Phosphatase evaluate? (2)
Liver 1. Damage 2. Function
What main body functions does ALT evaluate? (2)
Liver 1. Damage 2. Function
What main body functions does AST evaluate (2)?
Liver 1. Damage 2. Function
What main body functions does glucose evaluate? (2)
1. Liver function 2. Pancreatic endocrine function
What main body functions does sodium evaluate? (1)
Electrolyte balance
What main body functions does potassium evaluate? (1)
electrolyte balance
What main body functions does Amylase evaluate? (2)
1. Pancreas function 2. Renal function
What main body functions does CBC evaluate? (1)
Hemopoietic system
When assessing serum phosphorus level, the tests measure the _______ form of plasma phosphorus.
inorganic
Almost all the calcium in the blood is located in the ________.
plasma
All of the following are conditions that result in hypercalcemia, EXCEPT:
a. Osteolytic Bone Lesions
b. Hypoadrenocorticism
c. Vitamin D Toxicity
d. Parturient Paresis
d. Parturient Paresis
Phosphorus is present in blood in two forms: _____ phophate in plasma and in an ______ form in red blood cells.
-organic -inorganic
Nondiffusible protein-bound calcium makes up approximately ______% of serum calcium
40%
Name three things blood levels of calcium is regulated by
1. PTH 2. Calcitonin 3. Activated Vitamin D
The most common cause of hyperphosphatemia is:
renal insufficiency or failure
The main function of intracellular magnesium is:
an enzyme activator
The most common cause of hypomagnesemia is:
hypomagnesemic tetany in cattle and sheep
The most common cause of hypomagnesemia is:
renal failure
T or F Hemolysis will cause falsely increased magnesium results
T
The intestine and __________ regulate the serum level of phosphorus through the actions of Vitamine D and PTH.
kidney