Physio

Question 1

the ECF, about
50 percent of the calcium is ..,
41 percent is .., and
9 percent is …..

Answer 1

in the free divalent cation form

loosely bound to proteins

in the nonionized form, combined with anionic substances such as phosphate and citrate.

Question 2

The most important factor controlling renal reabsorption of calcium, and therefore calcium excretion, is …

Answer 2

PTH

Question 3

PTH can greatly increase …, thereby playing an important role in control of plasma phosphate concentration and calcium concentration.

Answer 3

renal phosphate excretion

Question 4

Bone Is Continually Deposited by … and Resorbed by .., a Dynamic
Process Referred to as …

Answer 4

Osteoblasts

Osteoclasts

Remodeling

Question 5

Vitamin D plays a major role in

Answer 5

calcium absorption from the intestinal tract and in
bone deposition and remodeling

Question 6

Actions of Vitamin D

Answer 6

• It functions as a type of hormone to promote intestinal absorption of calcium.
• It promotes phosphate absorption by the intestines.
• It has a weak effect to decrease renal calcium and phosphate excretion.
• It plays an important role in bone resorption, as well as bone deposition.

Question 7

PTH Secretion Is Regulated by

Answer 7

Extracellular Calcium Concentration .

Question 8

PTH formation is strongly regulated by ECF calcium ion concentration; small decreases in the concentration of the ion result …

Answer 8

in large increases in PTH formation

Question 9

PTH Mobilizes .. From Bone

Answer 9

Calcium and Phosphate

Question 10

PTH …. Renal Calcium Excretion and … Phosphate Excretion.

Answer 10

Decreases

Increases

Question 11

PTH greatly increases
calcium and phosphate absorption from the intestines by

Answer 11

increasing formation in the kidneys of 1,25­dihydroxycholecalciferol from vitamin D.