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Pharmacology Test #5 > Osteoporosis > Flashcards

Flashcards in Osteoporosis Deck (73)
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1

Calcium in the bone is

hydroxyapatite [Ca10(PO4)6(OH)2]

2

Osteoblasts

bone forming cells

3

Osteoclasts

bone resorption cells

4

Factors released by osteocytes that stimulates osteoblasts

prostaglandins, NO, dentin matrix protein-1

5

Factors released by osteocytes that stimulates osteoclasts

sclerostin; osteocalcin; MEPE (matrix extracellular phosphoglycoprotein)

6

What does parathyroid hormone (PTH) do?

1. increased calcium reabsorption from CT
2. increased calcium resorption from bone
3. increased PO4 loss in urine
4. increased 1,25(OH)2D3 production by kidney

7

PTH secretion is triggered by

low serum Ca2+ levels

8

First step of vitamin D synthesis

7-dehydrocholesterol -> (UV) -> cholecalciferol (D3)

9

Cholecalciferol can be obtained

in the diet or via exposure to sun light

10

Under which conditions is 25-hydyoxyvitamin D3 converted into 1,25 Dihydroxy vit D3 (calcitriol)?

low phosphorus and Ca2+
(PTH)

11

Under which conditions is 25-hydyoxyvitamin D3 converted into 24,25 Dihydroxy Vit D3 (secalciferol)?

normal phosphorus and calcium

12

What reaction does 1-alpha-hydroxylase catalyze?

25-hydyoxyvitamin D3 -> 1,25 Dihydroxy vit D3 (calcitriol)

13

What reaction does 24-hydroxylase catalyze?

25-hydyoxyvitamin D3 -> 24,25 Dihydroxy Vit D3 (secalciferol)

14

Actions of vitamin D

1. increased calcium and PO4 absorption from small intestine
2. increased calcium and PO4 reabsorption
3. indirect (slow) effects on cells
4. feedback inhibition of PTH (1,25(OH)2D

15

What is upregulated by Vitamin D3?

1. TrpV6
2. Calbindin-D9k
3. Ca2+-ATPase

16

Which cells secrete calcitonin?

cells in the thyroid gland

17

What does calcitonin do?

negative regulator of serum calcium;
1. inhibits osteoclastic bone resorption
2. increases calcium and PO4 loss in the urine

18

What is calcitonin stimulated by?

high serum calcium levels

19

Describe postmenopausal osteoporosis.

decrease in estrogen levels causes a decrease in bone mass; shift in bone remodeling balance toward resorption; spontaneous or minimal trauma fractures

20

Describe osteoporosis related to aging.

caused by age-related decrease in osteoblast activity in both men and women

21

Vertebral complications of osteoporosis

fragility fractures; pain; height loss; kyphosis; activity limitations; restrictive lung disease; psychological symptoms

22

Risk factors for osteoporosis

Physical inactivity; age; low calcium intake in early years; long-term glucocorticoid therapy

23

Hyperparathyroidism

increased bone resorption and decreased calcium excretion

24

Hypercalcemia caused by malignant tumors

some tumors produce a peptide with PTH activity

25

CNS complications from hypercalcemia

depression and coma

26

Hypocalcemia can be caused by

hypoparathyroidism or vit. D deficiencies

27

Symptoms of hypocalcemia

causes neuromuscular disturbances, parasthesias, tetany, and muscle cramps

28

Rickets

Vitamin D deficieny; weight bearing bone deformities in children

29

Vitamin D preparations

Cholecalciferol Vit D3 (OTC)
Calcifediol 25(OH)Vit D3 (Calderol)
Calcitriol 1,25(OH)2VitD3 (Rocaltrol)

30

MOA of Vitamin D supplements

increased calcium and PO4 absorption from gut
increased calcium and PO4 reabsorption in renal tubules