Week 8: Ca2+, Mg2+, and PO4- handling Flashcards

1
Q

Functions of intracellular [Ca2+]

A
  • second messenger
  • Muscle contractility
  • Cell motility
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2
Q

Extracellular Ca2+ functions

A
  • Excitation-contraction coupling in muscle
  • Synaptic transmission
  • Platelet function & coagulation
  • Primary regulator of PTH secretion
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3
Q

Why are Ca2+ levels so tightly regulated

A

because it can effect the potentials of excitable cells

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4
Q

issue with Hypocalcemia and excitable cells

A

Spontaneous depolarization

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5
Q

Issue with hypercalcemia on excitable cells

A

Depolarization hurdle

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6
Q

Where is most of the Ca2+ in the body

A

99% of total body Ca2+ and 85% Phosphate contained within the skeleton (hydroxyapatite)

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7
Q

How does Ca2+ circulate

A

46% bound to albumin

6% bound to small anions (citrate, phosphate, lactate)

48% biologically free active Ca2+ in feedback loops

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8
Q

How is rapid release of Ca2+/Pi mediated

A

mediated by PTH and Vitamin D acting directly on osteoblasts and indirectly on osteoclasts to resorb the bone

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9
Q

Describe Ca2+ flux between body compartments

A
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10
Q

Describe the effect of pH, plasma protein & citrate on total & free Ca2+

A

corrected or adjusted total Ca2+

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11
Q

Describe the bone remodeling process

A
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12
Q

What happens when too much bone is resorbed?

A
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13
Q

Ca2+/Pi maintenance

A
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14
Q

Where are the PT glands located?

A
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15
Q

Transfusions and Ca2+

A

preservative is citrate and adding a lot of citrate to someone can soak up a person’s Ca2+

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16
Q

Overview of Ca/P maintenance

A
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17
Q

Describe PTH synthesis and Secretion

A
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18
Q

Describe how Ca2+ is sensed by the PT glands

A
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19
Q

Describe other factors regarding PTH secretion

A
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20
Q

How is PTH gene transcription regulated?

A

Calcitriol inhibits PTH gene transcription

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21
Q
A
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22
Q

Low plasma Mg2+ effects on PTH

A

stimulates secretion of PTH

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23
Q

High plasma Mg2+ effects on PTH

A

Inhibits secretion of PTH

24
Q

Mg2+ depletion effects on PTH

A

Paralyzes secretion

(Mg2+ second messenger in relay from CaSR to PTH secretion ( ie hypocalcemia in neonates with diarrheal disease)

25
Q

Describe PTH metabolism

26
Q

Describe PTH clearance

27
Q

Describe PTH action in the kidney

28
Q

Describe PTH action in bone

29
Q

Describe RANKRANKL action

30
Q

PTH action in bone additional

31
Q

PTHrP AKA

A

PArathyroid hormone related peptide

32
Q

PTHrP functions

33
Q

Describe Pi features

34
Q

How is plasma [Pi] regulated

35
Q

Etiologies of hypocalcemia

36
Q

Etiologies of hypercalcemia

37
Q

Etiologies of hyppphosphatemia

38
Q

Etiologies of Hyperphosphatemia

39
Q

Consequences of hypocalcemia

40
Q

Consequences of hypercalcemia

41
Q

Consequences of hypophosphatemia

42
Q

Consequences of hyperphosphatemia

43
Q

Primary hyperparathyroidism vs hypercalcemia of malignancy vs hypoparathyroidism

44
Q

Review of Vitamin D3

45
Q

Describe Calcitriol synthesis

46
Q

Describe Calcitriol targets and activity

47
Q

Describe Calcitriol MOA

48
Q

Describe the general action of nuclear steroid receptors

49
Q

Describe VDR expression

50
Q

What genes are regulated by Calcitriol

51
Q

How is calcitriol regulated?

52
Q

Describe 24-hydroxylase deficiency

53
Q

What is Calcitonin?

54
Q

Normocalcemia

A

absorption = secretion

55
Q

Hypocalcemia

56
Q

Hypercalcemia

57
Q

Describe the regulation of Plasma {Mg2+]