Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Bone Mineral Homeostasis > Flashcards

Bone Mineral Homeostasis Flashcards

1
Q

what stimulates thyroid gland to secrete calcitonin and what stimulates it to secrete PTH?

A

Parafollicular C cells –> calcitonin –> reduce uptake of Ca2+ –> decreased plasma Ca2+

Parathyroid Chief cells –> PTH –> increase uptake of Ca2+ –> increased plasma Ca2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how does PTH affect plasma phosphate

A

PTH works on kidney to reduce phosphate reabsorption –> increased urinary phosphate –> decreased plasma phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how does calcitonin affect plasma phosphate

A

increased plasma calcitonin works on kidney to decrease both calcium and phosphate reabsorption –> increased urinary phosphate –> decreased plasma phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how does magnesium affect PTH secretion

A
  • moderate decline in Mg –> enhanced PTH secretion

- severe decline in Mg –> decreased PTH secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are common causes of decreased magnesium

A

CADCA

Chronic Diarrhea
Alcohol Abuse
Diuretics
Chronic PPI
Aminoglycoside use
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

mechanism of vitamin D’s transformation to its active form

A

vitamin D (taken up by skin from sun) uses 7-dehydrocholesterol –> Cholecalciferol (vitamin D3) uses 25 hydroxylase in liver –> 25-hydroxyvitamin D3 uses 1 alpha hydroxylase in kidney —> 1, 25-dihydroxycholecalciferol aka calcitriol

or get vitamin D from diet in form of ergocalciferol (vitamin D2) or vitamin D3 which is taken up by liver and using 25 hydroxylase –> 25 hydroxyvitamin D3 which uses 1 alpha hydroxylase in kidney –> 1, 25 dihydroxycholecalciferol aka calcitriol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the effect of 1,25-dihydroxycholecalciferol aka calcitriol on calcium and phosphate metabolism

A
  • in bone promotes PTH secretion
  • in intestine –> increases calcium and phosphate absorption
  • in kidney –> increases calcium and phosphate reabsorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what produces fibroblast growth factor 23

A

osteoblasts and osteoclasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the function of fibroblast growth factor 23

A

inhibits calcitriol production and phosphate reabsorption in kidney –> increased phosphate excretion by kidney –> reduced serum phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the non hormonal regulators of bone mineral homeostasis

A

Biphosphonates
Fluoride
Calcimimetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the hormonal regulators of bone mineral homeostasis

A 
Vitamin D
PTH
Calcitonin
Estrogen
Glucocorticoids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does PTH increase osteoclast AND osteoblast activity in bone

A

via ligand RANKL, a TNF cytokine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

mechanism of PTH

A

couples Gs receptors and increases cAMP in bone and renal tubular cells –> bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

recombinant PTH analogue

A

Teriparatide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how does the doses of the PTH analogue stimulate different function (name it)

A

Teriparatide

  • pulsatile doses –> bone formation
  • large does –> resorption aka bone breakdown to increase calcium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

function of Teriparatide

A
  • Osteoporosis (pulsatile dose)

- Restores normal bone loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

AE of Teriparatide

A

Hypercalcemia
Hypercalciuria

If used for longer than 2 years: increased risk of osteosarcoma

18
Q

what is the RANKL (RANK ligand) inhibitor and what is its mechanism

A

Denosumab –> monoclonal antibody that binds to RANKL –> prevents it from binding and stimulating osteoclastic (RANK) activity

19
Q

use of Denosumab

A

used to inhibit bone resorption hence treating osteoporosis

20
Q

AE of denosumab

A

increased risk of infections

21
Q

what are the two types of Vitamin D dependent Rickets

A

Type I: defective 1 alpha hydroxylase enzyme –> reduced calcitriol –> decreased calcium and phosphate

Type II: defective receptor for vitamin D

22
Q

what is Calcitriol used to treat

A

secondary hyperparathyroidism in patients with chronic renal failure and liver disease

23
Q

what is Calcipotriol used to treat (what is chemical name for it)

A

Calcipotriene

psoriasis (topical application)

24
Q

who are vitamin D supplements given to (name the vitamin D given)

A

Vitamin D2 - Ergocalciferol
Vitamin D3 - Cholecalciferol

Chronic renal failure
Osteoporosis
Nutritional rickets with inadequate intake
Chronic Liver failure

25
Q

AE of vitamin D

A

chronic over dose –> hypercalcemia and hyperphosphatemia

26
Q

name the phosphate binding drug and what it is used for

A

Sevelamer –> prevent hyperphosphatemia in those with chronic renal failure and can’t excrete the phosphate

binds phosphate and prevents reabsorption in GI

27
Q

oral calcium prep and what it is used for

A

Oral: Ca carbonate, Ca citrate, Ca lactate

counteract overdose of magnesium sulfate used in eclampsia

28
Q

IV calcium prep and what it is used for

A

Calcium gluconate – used for hypocalcemic tetany

29
Q

AE of calcium preps

A

IM: necrosis and abscess formation
IV: thrombophlebitis

30
Q

form of calcitonin that has a longer half life and potency? what it is used for?

A

Salmon calcitonin –> osteoporosis; increases bone mass and decreases spine fractures

31
Q

role of estrogen in bone mass

A

if given can reduce the amount of bone mass loss –> used in post menopausal women as a HRT and is more of a preventative measure

32
Q

AE of estrogen

A

Thromboembolism
Migraine
Increased risk of breast and endometrial cancer

33
Q

SERMs role in bone mass (Selective estrogen receptor modulators)

A

Tamoxifen: antagonist in breast but agonist in bone and endometrium

Raloxifene: antagonist in breast but agonist in bone; no effect in endometrium

both have beneficial effect in the bone

34
Q

AE of SERMS

A
  • Tamoxifen: endometrial cancer, thromboembolism, hot flushes
  • Raloxifene: thromboembolism, hot flushes
35
Q

what are the bisphosphonates

A

RAPE

Risedronate
Alendronate
Pamidronate
Etidronate

36
Q

mechanism of bisphosphonates (name them)

A

RAPE: Risedronate, Alendronate, Pamidronate, Etidronate

  • decrease osteoclast H+ ATPase –> disrupt mevalonate pathway –> decreases farnesyl pyrophosphate synthesis –> inhibits osteoclastic activity
  • bind with hydroxyapatite in bone –> reduce resorption
37
Q

uses of bisphosphonates (name them)

A

RAPE: risedronate, alendronate, pamidronate, etidronate

Osteoporosis, malignancy associated hypercalcemia, Paget’s disease of the bone

38
Q

why is there a history of ache, joint pain, or fractures in those that have paget’s disease

A

due to latent viral infection and association with genetic cause - chromosome 5 and 6

39
Q

which bisphosphonate is used for glucocorticoid induced osteoporosis

A

Alendronate

40
Q

AE of bisphosphonates

A

Erosive Esophagitis (direct irritation to lining)

Etridonate: Osteomalacia, Osteonecrosis of jaw and fractures

Chronic Etridonate and Pamidronate: bone malformation due to reduced osteoblastic activity

41
Q

how do you reduce the erosive esophagitis seen as AE of bisphosphonates

A

RAPE: risedronate, alendronate, pamidronate, etidronate

upright position after taking medication
increase fluid intake

Pharmacology (79 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions