Deck 40: Hormonal Regulation of Calcium and Phosphate Metabolism

Question 1

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

Answer 1

C

Question 2

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.

Answer 2

C

Question 3

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.

Answer 3

A

Question 4

Endogenous vitamin D synthesis begins in:

A)The intestines.
B)The kidneys.
C)The liver.
D)The skin.
E)Bone tissue.

Question 5

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.

Question 6

Osteoporosis can result from excessive production of receptor activator of nuclear factor $\kappa$ 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.

Question 7

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)