Bone Physiology

Question 1

The bone serves as what two types of reservoir?

Answer 1

• Rapid, readily exchangable

- Slow exchange (larger pool)

Question 2

What other component is regulated through bone resorption/formation?

Answer 2

phosphate

Question 3

What inhibits NaPi cotransporters?

Answer 3

PTH- causing a reduction in renal reabsorption

Question 4

What increases Ca and phosphate absorption?

Answer 4

Vitamin D

Question 5

What are the three primary hormones of calcium regulation?

Answer 5

1-Parathyroid Hormone (mobilizes calcium from bone and increase phosphate urinary excretion)
2-1,25 dihydrozycholecalciferol (vitamin D, increases calcium absorption from intestine and deposition to bone)
3-Calcitonin from thyroid (inhibits bone resorption)

Question 6

What 2 things happen when Ca decreases in the blood?

Answer 6

1-PTH is secreted stimulating Ca released from bone and reabsorption in kidneys)
2-release of active vitamin D to increase Ca uptake in intestines

Question 7

What 4 ways does Calcitonin lower blood Ca?

Answer 7

1-inhibit absorption in intestines
2-inhibit osteoclast
3-stimulate osteoblast
4-inhibit renal tubule reabsorption

Question 8

What 4 other hormones affect Ca metabolism?

Answer 8

1-Glucocorticoids
2-Growth Hormone
3-Estrogens
4-Insulin