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.Pharmacology > Part 19: Calcium Homeostasis > Flashcards

Part 19: Calcium Homeostasis Flashcards

1
Q

the thyroid gland makes ___, which is important to Ca homeostasis

A

calcitonin

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2
Q

where are the parathyroid glands found?

A

on either side of the thyroid gland

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3
Q

are the parathyroid glands regulated separately than the thyroid gland?

A

yes

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4
Q

what hormone is made by the parathyroid glands?

A

parathyroid hormone

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5
Q

bone is primarily made up of ___ and ___ arranged in a mineral matrix, making a strong skeletal structure and storing these minerals

A

Ca and phosphate

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6
Q

foods high in phosphates include:

A

meat and nuts

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7
Q

depending on the amount of Ca and PO4 in the body, what 2 things can happen to these minerals when eaten?

A
  1. if the body already has enough, the excess will be excreted from the body in feces
  2. if the body could use more, they will be reabsorbed into the blood through the intestine
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8
Q

the absorption of PO4 and Ca in the intestine is regulated by which vitamin?

A

vitamin D

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9
Q

once Ca and PO4 are absorbed in the blood, they can be used in what 2 ways?

A
  1. can be used immediately for cellualr processes

2. stored in bone

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10
Q

what happens with the absorbed Ca and Po4 is regulated by ____, ____ and ____

A

vitamin D, parathyroid hormone and calcitonin

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11
Q

any absorbed excess Ca and PO4 is excreted by the ____

A

kidneys

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12
Q

the adult human contains about ___kg of Ca and ___% is deposited in the bones and teeth

A

1; 99%

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13
Q

t/f Ca and PO4 are cycled in the body due to their involvement in many cellular processes

A

t

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14
Q

calcium is critical to cardiac muscle ___

A

contraction

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15
Q

phosphate is used in the biosynthesis of ____

A

ATP

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16
Q

the levels of Ca needed to initiate cellular processes is ____ (low/high) and demand changes ____ (slowly, rapidly)

A

low; rapidly

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17
Q

bone remodelling is a ____ process and occurs continually throughout life

A

dynamic

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18
Q

parathyroid hormone and vitamin D are involved in both ___ and ____ of bones to keep balance

A

formation and breakdown

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19
Q

the stimulation of ____ and ___cells happens in parallel to allow bone tissue to be balanced and maintained

A

osteoclasts & osteoblasts

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20
Q

an imbalance of osteoclast/osteoblast stimulation can lead to bone overgrowth (______) and breakdown (______)

A

osteopetrosis; osteoporosis

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21
Q

____ stimulates osteoblasta results in the secretion of ____, which increases activation of osteoclasts

A

PTH; RANKL

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22
Q

how do osteoclasts breakdown bone?

A

acidify the extracellular space around the bone, resulting in demineralization of Ca & PO4 from the bone surface

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23
Q

osteoblasts make new mineral deposits from ____

A

remaining serum Ca and PO4

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24
Q

PTH is secreted when Ca levels are ___ (high/low)

A

low

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25
Q

there are Ca sensing receptors on the surface of the ____cells so the parathyroid gland knows how much Ca is in the blood

A

parathyroid

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26
Q

when the Ca sensing receptors are activated, this activates the _____ pathway , resulting in the production of ____ within PT cells

A

arachidonic acid; leukotrienes

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27
Q

leukotrienes in the Pt cells promote the breakdown of ____, which prevents its release

A

PTH

28
Q

when PTH is secreted, it acts at the bone to increase___

A

demineralization and release of Ca and PO4 into the blood

29
Q

PTH ____ (lowers/increases) the activation of vitamin D in the kidney

A

increases

30
Q

vitamin D acts in several ways to ____ (increase/decrease) circulating levels of calcium and helps _____(build-up/breakdown) ca and PO4 stored in bone tissue

A

increase; build up

31
Q

PTH and vitamin D ___ (decrease/increase) bone resorption and make Ca and PO4 ____ (more/less) readily available for cellular processes

A

increases; more

32
Q

vitamin D acts in the GI tract to ____ (increase/decrease) the absorption of Ca and PO4 from food and _____ (increases/decreases) renal excretion

A

increase; decrease

33
Q

in what 2 ways can we get vitamin D?

A
  1. precursors from our food (or supplement)

2. made from cholesterol in the skin by UV light

34
Q

what is the active form of vitamin D?

A

1,25–dihydroxy vitamin D

35
Q

1,25–dihydroxy vitamin D is made from 2 metabolic steps, one in the ___ and the second in the ___

A

liver; kidney

36
Q

1,25–dihydroxy vitamin D is also called ___

A

calcitriol

37
Q

vitamin D is an important negative modulator of ____ to help maintain homeostasis

A

PTH

38
Q

vitamin D can increase both bone __ and __

A

formation and resorption

39
Q

how does vitamin D inhibit parathyroid hormone synthesis and release?

A

destablizing the hormone mRNA, preventing its translation into a functional hormone protein

40
Q

when the ca sensor pathway is activated, the secretion of ____ is reduced, which prevents excessive resoprtion and bone mineral loss

A

PTH

41
Q

calcitonin is a ____ (negative/positive) regulator of the actions of PTH and reduces bone mineral resorption

A

negative

42
Q

calcitonin is made by the ___

A

thyroid gland

43
Q

calcitonin is secreted in response to ___

A

high levels of circulating ca

44
Q

calcitonin release acts to inhibit ____ (bone cell) activity, which ____ (increases/decreases) the demineralization of the bone surface and ____(promotes/inhibits) the renal excretion of Ca and PO4 to prevent too high levels

A

osteoclast; decreases; promotes

45
Q

estrogen and growth hormone are ____ (negative/positive) modulators of bone formation

A

positive

46
Q

what happens to bone mass when estrogen decreases during menopause?

A

decreases

47
Q

low levels of growth hormone during development can lead to ___

A

dwarfism

48
Q

patients with _____ (hyper or hypo thyroidism) are at greater risk of developing osteoporosis

A

hyperthyroidim

49
Q

t/f physical forces on bones can affect bone remodelling

A

t

50
Q

give 2 examples of physical forces that can be used

A
  1. braces

2. weight-bearing exercises to reduce risk of osteoporosis

51
Q

an area of bone having force applied towards to it has a high level of activity of which bone cells?

A

osteoclasts (makes space for tooth to move to)

52
Q

braces reposition the ____ bones to straighten the teth

A

alveolar

53
Q

an area of bone having force pulled away from it has a high level of ____ (bone cell) activity

A

osteoblast (fill in space behind the moving tooth)

54
Q

what is osteoporosis?

A

a condition where the balance between bone resorption and formation tips toward a greater proportion of bone being broken down by osteoclasts

55
Q

____ can be used to slow the progression of osteoporosis

A

bisphosphates

56
Q

t/f hormone replacement can be given to help improve bone remodelling in menopasue

A

t

57
Q

what class does alendronate belong to?

A

bisphosphonates

58
Q

bisphosphonates are relatively simple molecules that have ___(#) ionically charged phosphate groups that bind to ___ on the surface of bone

A

2; Ca

59
Q

bisphosponates are also taken up by _____ (bone cells), reducing their activation

A

osteoclast

60
Q

bisphosphonates ____ (increase/decrease) bone remodelling

A

decrease

61
Q

bisphosphonates ____ (reduce/increase) reabsorption of bone mineral

A

reduce

62
Q

why do bisphosphonates have a long half life?

A

they bind ionically to bone mineral

63
Q

what is the usual dosing of bisphosphonates?

A

usually once weekly oral dosing

64
Q

how is bisphosphonates removed from the body?

A

excreted unchanged in the urine

65
Q

does the excretion of bisphosphonates require metabolizing enzymes?

A

no

66
Q

bisphosphonates have ____ (many /few ) drug interactions

A

few

.Pharmacology (55 decks)

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