Hormones Flashcards

1
Q

What are the 3 fractions in serum/plasma for Ca?

A

fCa: free calcium-hormones regulate this concentration

Ca/Pr: Protein Bound-Conc changes with protein conc

Ca/A: Bound to anions other than proteins-change with anion conc

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2
Q

Which type of Calcium should not filter through the glomerulus?

A

Protein bound

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3
Q

Where do animals get their Vit D from?

A

Hepatocytes make it or Diet

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4
Q

Horses don’t have which enzyme in the making of Vit D, so what do they rely on?

A

They dont have 1-hydroxylase

So they have to rely on Calcitriol

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5
Q

What regulates free Ca?

A

PTH and Vit D

altered by plasma pH

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6
Q

What happens when you have a low conc of Free Ca?

A

inc in PTH and Vit D

This mobilizes Ca from bone, inc absorption by intestines, and decreases the excretion by the kidneys

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7
Q

What tube do you use for analysis of Ca?

A

Purple or blue top

NOT EDTA or citrate will chelate

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8
Q

Whats happening if there is a change in total calcium?

A

Change in one or more fraction conc

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9
Q

What is Ca/Pr dependent on?

A

TP and Alb concentrations

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10
Q

What should the ratio be of the forms of Ca

A

Ca/A = 10%

Ca/Pr = 40%

fCa= 50%

There is never an equilibrium, so these are estimates

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11
Q

What are some causes of hypercalcemia?

A

Primary Hyperparathyroidism

Hypervitaminosis D

Dec Urinary Excretion

Humoral Hypercalcemia of malignancy (HHM)

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12
Q

Why would you have decrease in urinary excretion of Ca?

A

Renal Failure

Addisons-hypoadrenocortisim

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13
Q

Why is Equine Renal Failure Important

A

Dec GFR, dec clearance of Ca and Ca/A, which inc Free calcium. COMMON IN HORSES
bc of excess dietary Ca, switch from alfalfa to grass

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14
Q

Why does Adddisons create a hypercalcemia?

A

Hypovolemia-activation of RAAS-inc proximal tubular resoprtion of Na and Ca which increases free calc

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15
Q

What are some causes of hypocalcemia?

A

Hypoalbunimeia

primary hypoparathyroidism

hypovitaminosis D

Increase urinary excretion

Pregnancy/parturient/lactational

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16
Q

Why would hypoalbuminemia cause hypocalcemia?

A

remember Ca/Pr is controlled by proteins and albumin concentration and that any change in Total Ca could be due to any of the fractions

maybe inflammation?

17
Q

What is Rickets dz?

A

Lack of Vit D, calc or phosphate. leads to softening and weakening of the bones

18
Q

Would chronic renal dz lead to hypovitaminosis D? and why?

A

Yes-bc remember it causes secondary hyperparathyroidism which can cause and inc in PTH bc of dec Ca.

19
Q

What happens if you have a sudden addition of PO4 to plasma?

A

Ca/PO4 complexes form and those complexes are engulfed by macrophages and thus lowers both Ca and PO conc in plasma. The tissues that are already damaged will calcify

Healthy tissue does not calcify bc of hypercalcemia

20
Q

What tube do you use if you want to measure free ca?

A

Red top-Serum

21
Q

What happens if you get air in your free calcium sample?

A

pH shifts down which will cause more Ca to bind which means less free calcium.

As H+ leaves the protein, it frees a negative charge for Ca to bind to

22
Q

Disorders of total calcium are typically disorders of?

A

Free calcium

23
Q

What are the exceptions to the general statement of dz or tcal are of fcal?

A

Decrease in total cal due to hypoalbuminemia—bc this would be Ca/Pr

Inc binding of Ca to anions

24
Q

WHat are some reasons for hyperphosphatemia

A

Decreased urinary PO4 excretion-primary hypoparathryroidism

Inc absorption from intestine: phpsphate enema, hypervitaminosis D

Shifting from ICF to ECF-rhabdomyolysis

hemolysis

Age-GH increasing renal resorption

25
Q

Causes of Hypophosphatemia?

A

Increased urinary excretion

Decreased P03 absorption from intestine-anorexia

Shift from ECF to ICF-hyperinsulinisn

Defective mobilization of PO4 from bone

26
Q

What are the 3 fraction of Mg

A

fMg-55%

Bound Mg-proteins and anions

TMg

27
Q

Does Mg play a role in PTH activity?

A

YES! essential!

28
Q

Where is most Mg found at?

A

Bones and Tissues

29
Q

What are some causes for hypermagnesemia?

A

Decreased urinary excretion-renal failure, dec GFR

Increased PTH

Pseudohypermagnesemia-in vitro hemolysis or delayed removal of RBCs from serum from clot

30
Q

Causes of hypomagnesemia

A

Hypoproteinemia

Anorexia

Osm diuresis, ketonuria

Grass tetany in cattle-high in PO4, and K but poor Mg absorption by rumen

31
Q

When does PTH become stimulated?

A

Decreased fCa and decreased vit D

32
Q

What could cause an increas in PTH

A

Neoplasms

Hypercalcemic disorders

Hyperplastic parathyroid glands: CRD-secondary hyperparathyroidism

33
Q

What could cuase a decrease in PTH

A

Damaged parathyroid gland

Inhibited parathyroid glands

34
Q

PTH-rp is produced by? and promotes/

A

Produced by many cells

Promotes Ca balance in fetus

35
Q

What are some causes of an increase serum PTH-rp

A

HHM

lymphoma, anal sac carcinoma, carcinomas

36
Q

What are you classic changes in CRF

A

Dec GFR- Inc P and Ca/A

Dec Vit D: dec Ca–PTH—inc Ca and dec P

If a porous Glom: Proteinuria: Dec Ca and P