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NeuroEndo Test 3 > Regulation of Calcium and Phosphate Metabolism > Flashcards

Regulation of Calcium and Phosphate Metabolism Flashcards

1
Q

Free, ionized Ca2+ is the biologically ___ form.

A

active

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2
Q

____ symptoms include hyperreflexia, spontaneous twitching, muscle cramping, tingling, and numbness.

A

Hypocalcemia

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3
Q

____ sign is twitching of the facial muscles elicited by tapping on the facial nerve and indicates _____.

A

Chvostek; hypocalcemia

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4
Q

____ sign is carpopedal spasm upon inflation of a BP cuff and indicates ____.

A

Trousseau; hypocalcemia

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5
Q

____ symptoms include decreased QT interval, constipation, lack of appetite, polyuria, polydipsia, muscle weakness, hyporeflexia, lethargy, and coma.

A

Hypercalcemia

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6
Q

Hypocalcemia reduces the activation threshold for Na+ channels, so it is ___ to evoke an AP, which results in membrane excitability.

A

easier

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7
Q

Generation of spontaneous APs is the physical basis for hypocalcemic ____ and produces tingling, numbness, and spontaneous muscle twitches.

A

tetany

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8
Q

Hypercalcemia causes ____ membrane excitability, so the nervous system becomes depressed and reflex responses are slowed.

A

decreased

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9
Q

An increase in plasma protein concentration ____ total Ca2+ concentration.

A

increases

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10
Q

An increase in Ca2+ complexed with anions will ____ ionized Ca2+ concentration.

A

decrease

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11
Q

Acid-base abnormalities will alter the ionized concentration of Ca2+ by changing the fraction of Ca2+ bound to ____.

A

albumin

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12
Q

Acidemia ____ free ionized Ca2+ concentration because ___ Ca2+ is bound to albumin.

A

increases; less

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13
Q

Alkalemia _____ free ionized Ca2+ concentration because ___ Ca2+ is bound to albumin.

A

decreases; more

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14
Q

Alkalemia is often accompanied by _____.

A

hypocalcemia

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15
Q

Extracellular concentration of Pi is ___ related to that of Ca2+.

A

inversely

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16
Q

The chief cells of the parathyroid glands synthesize and secrete ___.

A

PTH

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17
Q

PTH is stimulated to be secreted when there are ___ levels of plasma Ca2+.

A

low

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18
Q

High extracellular Ca2+ concentration ____ PTH synthesis and secretion.

A

inhibits

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19
Q

Chronic hypercalcemia causes ___ synthesis and storage of PTH, ___ breakdown of stored PTH, and release of inactive PTH fragments into circulation.

A

decreased; increased

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20
Q

Chronic hypocalcemia causes ___ synthesis and storage of PTH and hyperplasia of parathyroid glands (secondary hyperparathyroidism).

A

increased

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21
Q

Severe hypomagnesemia (ie alcoholism) ____ PTH synthesis, storage, and secretion.

A

inhibits

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22
Q

PTH acts as a ___.

A

GPCR

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23
Q

Decreased plasma Ca2+ concentration leads to ___ PTH secretion. This leads to ___ bone resorption; ___ Pi reabsorption, ___ Ca2+ reabsorption, and ___ urinary cAMP by the kidneys; and ___ Ca2+ absorption (indirect via VitD) by the intestine.

A

increased; increased; decreased; increased; increased; increased

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24
Q

____ __ promotes mineralization of new bone through its coordinated actions in the regulation of both Ca2+ and Pi plasma concentrations.

A

Vitamin D

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25
Q

Vitamin D ___ both Ca2+ and Pi plasma concentrations.

A

increases

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26
Q

PTH receptors are located on ____.

A

osteoblasts

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27
Q

Short-term actions of PTH include bone ____ via direct action on osteoblasts.

A

formation

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28
Q

Long-term actions of PTH include increased bone ___ via indirect action of osteoclasts mediated by cytokines released from osteoblasts.

A

resorption

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29
Q

Vitamin D acts synergistically with PTH to stimulate ____ activity and bone ____.

A

osteoclast; resorption

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30
Q

____ induces stem cells to differentiate into osteoclast precursors, mononuclear osteoclasts, and finally, mature, multinucleated osteoclasts.

A

M-CSF

31
Q

____ is a cell surface protein produced by osteoblasts, bone lining cells, and apoptotic osteocytes. This is the primary mediator of osteoclast formation.

A

RANKL

32
Q

____ is a cell surface protein receptor on osteoclasts and osteoclast progenitors.

A

RANK

33
Q

___ is a soluble protein produced by osteoblasts, is a decoy receptor for RANKL, and inhibits RANKL/RANK interaction.

A

OPG (osteoprotegerin)

34
Q

PTH ___ RANKL and ___ OPG.

A

increases; decreases

35
Q

Vitamin D ___ RANKL.

A

increases

36
Q

Inhibition of Na+-P transporter by PTH causes ____.

A

phosphaturia

37
Q

___ in PTH causes urinary cAMP.

A

increase

38
Q

PTH ____ 1-alpha-hydroxylase activity in the kidney.

A

stimulates

39
Q

PTH stimulates osteoblastic ___ and ___.

A

growth; survival

40
Q

Sustained elevated levels of PTH shift the balance to a relative increase in osteoclast activity, thereby ___ bone turnover and ____ bone density.

A

increasing; reducing

41
Q

PTH stimulates Ca2+ ____ in the kidney.

A

reabsorption

42
Q

Vitamin D ___ Ca2+ and Pi absorption in the small intestine.

A

increases

43
Q

Vitamin D sensitizes osteoblasts to ___ in the bone.

A

PTH

44
Q

____ regulates osteoid production and calcification.

A

Vitamin D

45
Q

Vitamin D promotes Pi _____ by proximal nephrons in the kidney.

A

reabsorption

46
Q

Vitamin D has ____ actions on Ca2+ in the kidney.

A

minimal

47
Q

Vitamin D directly ___ PTH gene expression in the parathyroid gland.

A

inhibits

48
Q

Vitamin D directly ___ CaSR gene expression in the thyroid gland.

A

stimulates

49
Q

____ is a G-protein coupled receptor which senses extracellular levels of calcium ion.

A

CaSR

50
Q

____ decreases blood Ca2+ and Pi concentrations by inhibiting bone resorption.

A

Calcitonin

51
Q

Calcitonin receptors are expressed on ___.

A

osteoclasts

52
Q

____ plasma Ca2+ concentration stimulates calcitonin to be released.

A

Increased

53
Q

Calcitonin ___ have a role in chronic regulation of plasma Ca2+ concentration.

A

doesn’t

54
Q

_____ stimulates intestinal Ca2+ absorption and renal tubular Ca2+ reabsorption.

A

Estradiol-17-beta

55
Q

Estrogen promotes ____ of osteoblasts and ____ of osteoclasts, favoring bone ____ over ____.

A

survival; apoptosis; formation; resorption

56
Q

Adrenal glucocorticoids (ie cortisol) ____ bone resorption and renal Ca2+ wasting, and ____ intestinal Ca2+ absorption.

A

promote; inhibit

57
Q

Primary hyperparathyroidism has ___ PTH, ___ Ca2+, ___ Pi, and ___ VitD.

A

high; high; low; high

58
Q

____ hyperparathyroidism causes high PTH levels secondary to low Ca2+ concentration in blood.

A

Secondary

59
Q

Secondary hyperparathyroidism caused by renal failure has ___ PTH, ___ Ca2+, ___ Pi, and ___ VitD.

A

high; low; high; low

60
Q

Secondary hyperparathyroidism caused by VitD deficiency has ___ PTH, ___ Ca2+, ___ Pi, and ___ VitD.

A

high; low; low; low

61
Q

___ presents with symptoms of low Ca2+ and is treated with oral Ca2+ supplement and an active form of VitD.

A

Hypoparathyroidism

62
Q

Hypoparathyroidism has ___ PTH, ___ Ca2+, ___ Pi, and ___ VitD.

A

low; low; high; low

63
Q

Albright hereditary osteodystrophy (pseudohypoparathyroidism type 1a) has ___ PTH, ___ Ca2+, ___ Pi, and ___ VitD.

A

high; low; high; low

64
Q

Pseudohypoparathyroidism type 1a has high PTH levels. Administration of exogenous PTH produces __ phosphaturic response and __ increase in urinary cAMP.

A

no; no

65
Q

Patients with _____ ___ ___ present with short stature, short neck, obesity, subQ calcification, and shortened metatarsals and metacarpals.

A

Pseudohypoparathyroidism type 1a

66
Q

Humoral hypercalcemia of malignancy has __ PTH, __ Ca2+, __ Pi, and __ VitD.

A

low; high; low; low

67
Q

Familial hypocalciuric hypercalcemia (FHH) has ___ PTH, ___ serum Ca2+, ___ urine Ca2+, ___ Pi, and ___ VitD.

A

normal/high; high; low; normal; normal

68
Q

___ is causes by mutations that inactivate CaSR in parathyroid glands and parallel Ca2+ receptors in the ascending limb of the kidney. This results in hypocalciuria and hypercalcemia.

A

FHH

69
Q

____ is caused by impaired vitamin D metabolism.

A

Rickets-Osteomalacia

70
Q

Vitamin D-dependent rickets type 1 is caused by low _____.

A

1-alpha-hydroxylase

71
Q

Vitamin D-dependent rickets type 2 is caused by low ____.

A

vitamin D receptor

72
Q

____ ____ can originate from either a GI disorder, suboptimal nutrition, or inadequate sun exposure.

A

Nutritional osteomalacia

73
Q

Vitamin D deficiency presents with ___ PTH, ___ serum Ca2+, ___ serum Pi, ___ urine Pi, ___ urine cAMP, and ___ vitamin D.

A

high (secondary); normal/low; low; high; high; very low

NeuroEndo Test 3 (13 decks)

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