Question

the diagram below shows the effects of parathyroid hormone and calcitonin on regulating on blood calcium levels. drag and drop the options to the correct box, either an effect of pth or an effect of calcitonin to normalize blood calcium levels. calcium in the blood normal: 8.5 - 10.8 mg/dl blood calcium falls (<8.5 mg/dl) blood calcium rises (>10.8 mg/dl) parathyroid hormone (pth) secreted from the parathyroid glands calcitonin secreted from the thyroid gland increases osteoclast activity (bone breakdown) increases osteoblast activity (bone formation) increases calcium retention in the kidneys stimulates vitamin d activity inhibits vitamin d activity decreases calcium absorption in the small intestine decreases calcium retention in the kidneys. increases calcium absorption in the small intestine

Explanation:

Parathyroid hormone (PTH) is secreted when blood calcium falls. Its effects include increasing osteoclast activity (bone breakdown) to release calcium into the blood, increasing calcium retention in the kidneys to prevent calcium loss in urine, and stimulating vitamin D activity which in turn increases calcium absorption in the small intestine. Calcitonin is secreted when blood calcium rises. Its effects include increasing osteoblast activity (bone formation) to take up calcium from the blood and deposit it in bone, inhibiting vitamin D activity (so as to decrease calcium absorption in the small intestine), decreasing calcium absorption in the small intestine, and decreasing calcium retention in the kidneys (so that more calcium is excreted in urine).

Answer:

Effects of PTH:

• Increases osteoclast activity (bone breakdown)
• Increases calcium retention in the kidneys
• Stimulates vitamin D activity
• Increases calcium absorption in the small intestine

Effects of Calcitonin:

• Increases osteoblast activity (bone formation)
• Inhibits vitamin D activity
• Decreases calcium absorption in the small intestine
• Decreases calcium retention in the kidneys