Biology question

[InternDoc]

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which is function of calcitonin ?
1. causes a deposition of bone matrix by inhibiting bone resorption and increasing osteoblast activity
2. increases blood Ca+ via stimulation of bone resorption
3. it's secreted by Parathyroid gland
4. it promotes Ca+ reabsorption in the kidney tubules

 

[slick cat]

which is function of calcitonin ?
1. causes a deposition of bone matrix by inhibiting bone resorption and increasing osteoblast activity
2. increases blood Ca+ via stimulation of bone resorption
3. it's secreted by Parathyroid gland
4. it promotes Ca+ reabsorption in the kidney tubules

the first choice is correct b/c calcitonin decrease bone resorption (inhibits activity of osteoclast) and increases bone formation (increases activity of osteoblast); it also decreases Ca+ levels in the blood and is secreted by the thyroid gland (eliminates answers 2 and 3). Calcitonin also inhibits Ca+ reabsorption in the kidney tubules and results in the lost of Ca+ in the urine (eliminates answer 4).

 

[DrMattOglesby]

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[slick cat]

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hmm, I am looking at a chart in my general bio book and it says that the thyroid gland secretes T3, T4, and calcitonin and that the parathyroid secretes parathyroid hormone (PTH), which has an antagonistic effect to calcitonin (it increases blood calcium levels by stimulating osteoclasts to break down bone and release calcium). I also looked in the Kaplan book and search engines online but I guess I must be wrong in my assumption. Oh well, can't fault me for trying.

 

[RxWildcat]

1, google is your friend

 

[beckhamtheman]

1 because calcitonin decreases blood calicum level and it does that by increasing osteoblast activity. osteoblasts will make bone using calicum so decreases its level from the bood.