Bone Growth and Hormonal Regulation Quiz

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Which hormone stimulates osteoclasts to resorb bone when calcium or phosphorus levels are low?

Calcitonin
Teriparatide
Estrogen
Parathyroid hormone (PTH) (correct)

What is the role of PTH in facilitating calcium absorption?

It stimulates the intestines to absorb more calcium and the kidneys to activate more vitamin D. (correct)
It has no role in calcium absorption.
It reduces bone resorption stimulated by calcitonin.
It increases the secretion of endogenous calcitonin to decrease serum calcium levels.

What is the role of estrogens in bone remodeling?

They increase the risk for osteoporosis in postmenopausal women.
They have no role in bone remodeling.
They stimulate osteoclasts to resorb bone.
They reduce bone resorption stimulated by PTH. (correct)

Which hormone balances the action of PTH by shutting down osteoclastic activity and increasing osteoblastic activity in the presence of hypercalcemia?

Calcitonin (B) Signup and view all the answers

Why were all previously marketed calcitonin drugs pulled off the market?

They were associated with an increased risk of cancer. (D) Signup and view all the answers

What are teriparatide (Forteo) and abaloparatide (Tymlos)?

Synthetic injectable PTH analogues derived from recombinant DNA technology. (D) Signup and view all the answers

Which supplement is recommended to be taken with calcium to improve calcium uptake?

Vitamin K (C) Signup and view all the answers

What is the recommended vitamin D level before initiating bisphosphonate therapy?

Greater than 30 ng/mL (A) Signup and view all the answers

Which population is now being encouraged to take calcium and vitamin D supplements?

Community-dwelling postmenopausal women without a fracture history (A) Signup and view all the answers

What percentage of calcium is typically absorbed from dietary sources?

10% to 12% (D) Signup and view all the answers

Which type of patients might prefer calcium citrate over calcium carbonate due to better absorption?

Patients with high gastric pH (B) Signup and view all the answers

What is the primary purpose of taking calcium and vitamin D supplements in older adults?

Prevention of osteoporosis (B) Signup and view all the answers

Which population should avoid whole milk after the age of 12 months?

Infants after 12 months of age (C) Signup and view all the answers

What can greatly affect the amount of calcium in the diet and make supplementation mandatory?

Milk allergy (D) Signup and view all the answers

What is the recommended daily maximum dose of vitamin D supplements?

10,000 IU/d (B) Signup and view all the answers

Which of the following is considered a first-line therapy for osteoporosis according to the guidelines mentioned in the text?

Bisphosphonates (C) Signup and view all the answers

Which of the following combinations is mentioned in the text as having potential additive effects on bone mineral density (BMD)?

Both A and B (B) Signup and view all the answers

Which of the following statements is true regarding the combination of teriparatide and denosumab?

It had a much more positive impact than each used separately, especially on femoral neck and hip density. (B) Signup and view all the answers

Which of the following statements is true regarding the use of fluoride for bone health?

Fluoride stimulates bone growth, but the bone may be weaker than naturally developed bone. (D) Signup and view all the answers

Which of the following statements is true regarding the use of calcium supplements?

Calcium supplements alone rarely need blood test follow-up. (C) Signup and view all the answers

Which of the following statements is true regarding the use of vitamin D supplements alone?

Vitamin D alone is ineffective for osteoporosis treatment or risk reduction. (D) Signup and view all the answers

Which of the following statements is true regarding the use of Selective Estrogen Receptor Modulators (SERMs) for osteoporosis treatment?

SERMs are effective in preventing fractures and have less cardiovascular risk than estrogen. (C) Signup and view all the answers

Which of the following statements is true regarding the use of estrogen for osteoporosis treatment?

Estrogen is effective in preventing fractures but has cardiovascular and cancer risks. (A) Signup and view all the answers

Which of the following statements is true regarding the use of alternative agents for bone health?

Findings from clinical trials on alternative agents such as phytoestrogens and isoflavones have been inconsistent in their support. (D) Signup and view all the answers

Which medication has been linked with atypical femur fractures similar to bisphosphonates?

Denosumab (D) Signup and view all the answers

What impact does inadequate vitamin D have on calcium absorption and PTH levels according to the text?

Decreases calcium absorption and increases PTH levels (A) Signup and view all the answers

Why is combination treatment with denosumab and immunosuppressants, steroids, and biologics not recommended?

Due to possible sepsis risk (D) Signup and view all the answers

What is the upper limit of daily intake for vitamin D supplements to avoid hypervitaminosis?

4,000 IU/day (B) Signup and view all the answers

Which form of vitamin D is more biologically active?

D1,25-dihydroxy (A) Signup and view all the answers

What is the serum level range for optimal bone health in terms of vitamin D?

$30$ to $50$ ng/mL (D) Signup and view all the answers

What can excess serum calcium deposits in soft, vascular plaque lead to?

$Less$ ability to regress in plaque (A) Signup and view all the answers

$100$ to $250$ mg of calcium are absorbed from the gut out of how much calcium consumed daily?

$500$ to $750$ mg (C) Signup and view all the answers

$D25$-dihydroxy, a form of vitamin D, is converted into which form in the liver?

$D1,25$-dihydroxy (C) Signup and view all the answers

What is the concern associated with taking calcium supplements without vitamin D?

Increased fracture rates (A) Signup and view all the answers

What is the primary mechanism of action for the drugs described in the text?

Stimulating bone formation, especially in the axial skeleton (D) Signup and view all the answers

What is the recommended duration of treatment with these drugs?

2 years (D) Signup and view all the answers

Which of the following patient populations is recommended to use these drugs according to the text?

Post-menopausal women at high risk for fracture (D) Signup and view all the answers

What is the main reason the text suggests for combining these drugs with IV bisphosphonate therapy or RANKL medications?

To have an additive impact on bone mineral density (C) Signup and view all the answers

Which of the following is a potential side effect associated with the use of these drugs described in the text?

Orthostatic hypotension (A) Signup and view all the answers

What is the main reason these drugs are considered third-line therapy for osteoporosis?

They have very limited indications (C) Signup and view all the answers

What is the main difference in storage requirements between teriparatide and abaloparatide described in the text?

Teriparatide requires refrigeration for 28 days, while abaloparatide does not (C) Signup and view all the answers

What is the primary role of denosumab (Prolia) as described in the text?

To inhibit osteoclast survival and function (A) Signup and view all the answers

What is the main concern associated with the use of denosumab (Prolia)?

Increased risk of osteonecrosis of the jaw (A) Signup and view all the answers

What is the main benefit of combining teriparatide with oral bisphosphonates as described in the text?

It does not provide any additional benefit (A) Signup and view all the answers

Parathyroid Hormone (PTH)

A hormone that stimulates osteoclasts to resorb bone when calcium or phosphorus levels are low.

PTH's role in calcium absorption

Stimulates intestines to absorb more calcium and kidneys to activate vitamin D.

Estrogen's role in bone remodeling

Reduces bone resorption stimulated by PTH.

Calcitonin's role

Balances PTH by decreasing osteoclastic activity and increasing osteoblastic activity in hypercalcemia.