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Flashcards in Calcium Deck (69):
1

Why is Ca important?

-nerve conduction
-bone formation
-muscle formation
-blood coagulation
-cerebral and cardiac function
-capillary permeability
-cell growth and division

2

the body contains ___kg of CA

1-2

3

How much Ca Is in the ionized (active) form?

50%

4

T/F: the ionized form is the most important form for calcium functions on heart, the nervous system, and bone formation

True

5

Of the non-ionized Ca, ___ is protein bound (primarily albumin) and ___ is combined with anions (diffusible)

41%, 9%

6

plasma calcium equilibrates with bone Ca++, but only ___ of bone Ca is readily exchangeable

0.5%
the rest is slowly exchangeable

7

T/F: Hypercalcemia causes nervous system excitement

FALSE - hypo

8

Hypocalcemia causes increased neuronal permeability to __, easy action potentials

Na

9

Chvostek's sign is caused by ___ and is recognized how?

hypocalcemia, tapping facial nerve leads to twitching

10

T/F: Hypocalcemia leads to a prolonged QT

TRUE

11

Hypocalcemia leads to __ and ___. most common is in the ____, carpopedal spasm

tetany, seizures, hand

12

The chief manifestation of hypercalcemia is

skeletal muscle weakness

13

S/S that are a result of HYPERca --> nervous system depression include

short qt, long PR interval, constipation, anorexia

14

Treatment for HyperCa

maintain UOP, hydrate, administer mithramycin in severe cases

15

The body contains __kg of phosphorus, and it is located __ skeletal, __% muscle/tissue, and __% ECF

1, 85, 15, 1

16

__% of Phos circulates in plasma protein bound

12

17

T/F Phos levels fluctuate significantly more than Ca++ because Ph moves between ECF and bone as well as between ECF and ICF

TRUE

18

Phos enters ECF via what 3 routes

GI, ICF, bone

19

phos leaves via what 3 routes

urine, ICF, bone

20

T/F The major control site for phosphorus is the liver

FALSE - kidney

21

___ increases urinary excretion of phos

parathyroid. Calcitonin to a lesser extent

22

GI absorption of Phos is increased by

1,25 D3

23

Parathyroid consists of __ glands

4

24

where is the parathyroid located

behind the upper and lower poles of the thyroid

25

Parathyroid contain mainly ___ cells and ___ cells

chief, oxyphil

26

T/F Oxyphil cells secrete PTH

FALSE Chief cells

27

Synthesis and secretion of PTH is related to ____ concentrations in the blood.

Calcium

28

3 reasons for parathyroid enlargement?

prolonged stimulation, pregnancy, lactation

29

calcium homeostasis slide???

look up

30

T/F PTH Increases reabsorption of Ca++ in the kidney's proximal tubules

FALSE - distal tubules

31

T/F PTH decreases reabsorption of phosphate in the renal tubules

TRUe

32

PTH increases ___ reabsorption to mobilize __ and ___

bone, ca, phos

33

PTH increases the production of 1,25-dihydroxycholecalciferol which is a Vit D metabolite which enhances _____

intestinal Ca++ absorption

34

the major stimulus for PTH is

low serum Ca++ level

35

Bone resorption is the process by which

osteoclasts break down bone and release Ca from bone fluid to blood

36

Rapid: activation of ____ for rapid reabsorption

bone

37

Delayed: activates/proliferates ___ for bone matrix break down

osteoclasts

38

increases in PTH results in ___ ca and ____ phosphate in the serum

increased, decreased

39

Increases in PTH results in increased excretion of ___, ____ and ___ by increasing ___ ___ and ____ reabsorption, largely in distal tubules and collecting ducts

phosphate, potassium, sodium, calcium, magnesium, hydrogen.

40

Where is calcitonin produced

the parafollicular (clear or C cells) of the thyroid

41

T/F Calcitonin has a similar affect of PTH

FALSE - opposite effect

42

Functions of Calcitonin:

inhibits bone reabsorption, increases urinary excretion of calcium

immediate: decreases osteoclastic activity and osteolysis of osteocytes
delayed: decreases osteoclast formation

43

calcitonin will cause ___ in serum ___ and ____ levels, and increased excretion of both

calcium, phosphate

44

T/F Excess or deficiency of calcitonin leads to defects in bone or calcium metabolism

FALSE- effect is weak

45

T/F Vitamin D has a potent effect to increase calcium absorption from the intestinal tract

TRUE

46

Vitamin D has important effects on both bone ____ and bone ____

deposition, absorption

47

T/F Vitamin D is an active substance

FALSE - must be converted to its active product 1,25 dihydroxycholecalciferol

48

Vitamin D3 is formed in the skin by _____

exposure to sunlight

49

Vitamin D3 is converted to 1.25-dihydroxycholecalciferol by the ____

liver

50

GI absorption of Ca++ is increased by _____

vitamin D

51

urinary excretion is _____ by PTH and _____ by calcitonin

decreased, increased

52

bone resorption is increased by ____ and inhibited by ____

PTH, calcitonin

53

____ is usually a result of a surgical damage to the glad during thyroid surgery

hypoparathyroidism

54

Calcium levels fall below normal in 24-72h which results in 4 things:

-tetany
(calcium ion interferes with membrane transport, interferes with the relaxation of the muscle)
-muscle cramps
-grand mal seizures
-cardiovascular collapse

55

treatment of hypoparathyroidism

-PTH (expensive, short half life)
-high ca and Vit D intake
(occasionally 1/25-D3 necessary)

56

T/F: hypomagnesemia can cause hypocalcemia resistant to calcium

TRUE - must treat first with magnesium. magnesium suppresses the release of PTH

57

primary hyperparathyroidism is caused by?

inappropriate hyper secretion of PTH resulting in hypercalemia

58

Primary hyperparathyroidism effects

-hypercalcemia
-hypercalciuria
-hypophosphatemia
-hyperphosphaturia
-bone mineralization
-shortened QT interval, depresses relaxation
-causes kidney stone formation as Ca+++ mobilized from bone must eventually be excreted by kidneys

59

most common cause of hyperparathyroidism is ____ hyperplasia or tumor

parathyriod

60

T/F Pregnancy may stimulate the parathyroids

TRUE

61

Secondary hyperparathyroidism is caused by

hypersecretion of PTH in response to hypocalcemic stress

62

secondary hyperparathyroidism results in

osteomalacia (inadequate mineralization of the bones)

63

vitamin D deficiency is caused by

-inadequate dietary syndrome - often due to fat malabsorption syndrome
-inadequate sunlight

64

Vit D deficiency results in ____ in adults and ____ in children

osteomalacia, rickets (bones fail to mineralize, epiphyses fail to fuse, epiphyseal plates widen and bowing and fractures occur)

65

T/F Vitamin D deficiency causes decreased absorption of ca and phos, decreased serum calcium and phosphate, increased PTH and increased bone resorption

TRUE

66

1g of calcium chloride contains the equivalent amount of ionized calcium as __g of calcium gluconate

3

67

Calcium therapy is indicated in patients with hypotension associated with either ___ or ___

CCB's or beta adrengeric blockers

68

calcium is indicated in causes of _____ as may occur in parturients being treated for preeclampsia

magnesium toxicity

69

calcium is contraindicated in patients with ____ as it may cause lethal arrhythmias

digoxin toxicity