Quiz 40: Hormonal Regulation of Calcium and Phosphate Metabolism

Endogenous vitamin D synthesis begins in: A)The intestines. B)The kidneys. C)The liver. D)The skin. E)Bone tissue.

Estrogen can oppose some of the effects of PTH.This occurs because of the effects of estrogen on: A)Intestinal enterocytes. B)Osteoclasts. C)Osteoblasts. D)Chief cells of the parathyroid gland. E)Proximal renal tubule cells.

Osteoporosis can result from excessive production of receptor activator of nuclear factor  light-chain enhancer of activated B cells (RANK)ligand (RANKL)by osteoblasts.A molecule that directly inhibits RANKL and protects bones from osteoclast overactivity is: A)PTH. B)Osteoprotegerin. C)Alkaline phosphatase. D)Osteoid. E)RANK.

The parathyroid glands respond rapidly to hypocalcemia.The protein responsible for the rapid response of the principal cells to a falling calcium level is: A)The PTH receptor. B)Membrane Ca⁺⁺-adenosine triphosphatase (ATPase). C)Ca⁺⁺-sensing receptor. D)The Na⁺-Ca⁺⁺ exchange antiporter. E)The transient receptor potential cation channel subfamily V,member 5 (TRPV5)calcium channel.

Lack of vitamin D can cause rickets in children.Of the following,which is the most important lifestyle activity that promotes normal endogenous vitamin D production? A)Playing outside. B)Exercising at a gym. C)Eating green vegetables. D)Consuming highly unsaturated oils (e.g.,olive oil). E)Drinking fruit juices.

The vitamin D receptor belongs to which class of receptors? A)G protein-coupled receptors B)Tyrosine kinase receptors C)Nuclear hormone receptors D)Calcium-sensing receptors E)Janus kinase/signal transducer and activator of transcription (JAK/STAT)receptors

PTH is secreted in a regulated manner.Which of the following directly increases PTH synthesis,secretion,or both? A)Elevated 1,25-dihydroxyvitamin D B)Decreased blood phosphate levels (hypophosphatemia) C)Decreased blood Ca⁺⁺ levels (hypocalcemia) D)Elevated blood K⁺ levels (hyperkalemia) E)Elevated Mg⁺⁺ levels (hypermagnesemia)