Vitamin D

Question 1

Vitamin D deficiency in young animals is called

Answer 1

Rickets

Question 2

Vitamin D deficiency in adult animals is called

Answer 2

Osteomalacia

Question 3

List 3 things vitamin D is important for

Answer 3

1. Bone and teeth formation
2. Intestinal absorption of calcium and phosphorus
3. Renal reabsorption of calcium and phosphorus

Question 4

1,25-dihydroxycholecalciferol’s primary function is to:

Answer 4

Increase calcium absorption from the intestine

Question 5

Cholecalciferol (D3) is a vitamin D precursor of ______ origin

Answer 5

Animal

Question 6

Ergocalciferol (D2) is a vitamin D precursor from ______ and ______

Answer 6

Fungi and plants

Question 7

______ is the active form of vitamin D

Answer 7

Calcitriol

Question 8

In the skin, 7-dehydrocholesterol is converted by sunlight into _______

Answer 8

Vitamin D3 (cholecalciferol)

Question 9

D3 (cholcalciferol) is converted into 25-hydroxycholecalciferol by ________ in the liver.

Answer 9

25-hydroxylase

Question 10

25-hydroxycholecalciferol is converted into 1,25-dihydroxycholecalciferol via _______ in the kidneys.

Answer 10

1-alpha-hydroxylase

Question 11

Vitamin D3 is also called _________

Answer 11

Cholecalciferol

Question 12

1,25-dihydroxcycholecalciferol is also called ______

Answer 12

Calcitriol

Question 13

25-hydroxycholecalciferol is also called ________

Answer 13

Calcidiol

Question 14

1 alpha-hydroxylase is a ______ enzyme in the kidney

Answer 14

Regulated

Question 15

25-hydroxylase is a _______ enzyme in the liver

Answer 15

Non-regulated

Question 16

PTH increases the synthesis of 1-alpha-hydroxylase. True or false?

Answer 16

TRUE

Question 17

Phosphorus, calcium, calcitriol, and FGF-23 provide negative feedback on the action of 1-alpha-hydroxylase. True or false?

Answer 17

TRUE

Question 18

25-hydroxycholecalciferol is converted into calcitriol via _________

Answer 18

1-alpha-hydroxylase

Question 19

Vitamin D inhibits ________ proliferation and _______ secretion

Answer 19

Chief cell proliferation and PTH

Question 20

Vitamin D increases absorption and reabsorption of _______ and _________

Answer 20

Calcium and phosphorus

Question 21

Vitamin D facilitates ________ resorption

Answer 21

Bone

Question 22

Vitamin D increases secretion of __________ from bone

Answer 22

FGF-23

Question 23

Vitamin D analogs can be used to treat hyperparathyroidism in small animals and people in order to __________________

Answer 23

Suppress parathyroid cell proliferation and PTH synthesis

Question 24

Vitamin D is has functions in immunomodulation and suppression of cell proliferation. True or false?

Answer 24

TRUE

Question 25

Why do animals with CKD have increased PTH concentrations?

Answer 25

Bum kidneys = decreased activation of Vitamin D
Vitamin D inhibits PTH; less vitamin D = less inhibition of PTH

Question 26

FGF-23 promotes excretion of ________

Answer 26

Phosphorus

Question 27

FGF-23 inhibits activation of __________

Answer 27

Vitamin D

Question 28

The active form of vitamin D (calcitriol) is produced in the ________

Answer 28

Kidneys

Question 29

PTHrp is important for cell ___________ and _________

Answer 29

Proliferation and differentiation