Which of the following statements regarding Ca²⁺ homeostasis is TRUE?

Question

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Parathyroid hormone (PTH) plays a crucial role in the regulation of Ca²⁺ homeostasis. PTH directly stimulates the reabsorption of Ca²⁺ from the kidneys, which helps to increase plasma Ca²⁺ levels. Option B is incorrect because PTH does not directly stimulate Ca²⁺ absorption from the GI tract. Option C is incorrect because in the absence of PTH, plasma Ca²⁺ levels would not be abnormally low, but rather they would be maintained by other mechanisms such as calcium release from bone. Option D is incorrect because when plasma Ca²⁺ increases above normal, the secretion of PTH decreases, not increases. Option E is incorrect because Vitamin D actually increases the renal tubular reabsorption of Ca²⁺.

Which of the Following Statements Regarding Ca2+ Homeostasis Is TRUE

Which of the Following Statements Regarding Ca²⁺ Homeostasis Is TRUE