Vitamin D

Question 1

Who discovered that after destroying the vitamin A content of cod liver oil by oxidation, it still possessed ability to cure rickets?

Answer 1

McCollum

Question 2

Who received the ultra-violet patent at U.W.

Answer 2

Steenbock

Question 3

Vitamin D promotes ___ and ___ absorption

Answer 3

Ca and P
-synthesis of a Ca-binding protein
-increase permeability of mucosal cells to Ca and P

Question 4

Where is and what is Ca and P absorbed as?

Answer 4

in the intestine as vit. D
-25-OH D in the liver
-1,25-(OH)2 in kidney

Question 5

Vitamin D is thought of as a ______

Answer 5

hormone

Question 6

Active form is made by the ____

Answer 6

kidney

Question 7

Active form travels to act on the _____ and ______

Answer 7

bones and intestines

Question 8

Vitamin D is required for normal ________

Answer 8

calcification
-amount varies with Ca and P amounts and ratio of Ca/P

Question 9

Highest requirements of vit. D are needed for:

Answer 9

-young and lactating animals
-swine and poultry
-wide Ca and P ratios

Question 10

What other two hormones are involved in calcification?

Answer 10

-calcitonin (lowers blood Ca levels and puts Ca back into bone)
-PTH (raises blood Ca levels and takes Ca out of bone)

Question 11

Rickets

Answer 11

disturbance of Ca and P metabolism - poor calcification of bones (occurs in young)

Question 12

Pigeon-breast

Answer 12

softening of bones in the chest, bowing of the chest

Question 13

Osteomalacia

Answer 13

failure of the bone matrix to become mineralized
-if mother is deficient possible congenital malformations
-importance of D to adults

Question 14

Where is vit. D primarily stored?

Answer 14

in liver
-no large transfer to fetus
-not as great ability to store as vit. A

Question 15

Vitamin D deficiency in chickens

Answer 15

-thin egg shells
-decreased hatchability
-decreased egg production

Question 16

Parturient paresis (milk fever) in dairy cows

Answer 16

-vitamin D deficiency
-found in lactating cows 1-24 hrs after calving
-drain of blood Ca into milk (plasma Ca declines)

Question 17

Parturient paresis (milk fever) symptoms

Answer 17

-lack of appetite
-dull and listless
-struggling and unable to stand
-low blood Ca and P
-coma

Question 18

__________ activates some precursor in the body and certain feeds for vit. D

Answer 18

radiant energy (sunlight)

Question 19

Ergocalciferol

Answer 19

vitamin D2

Question 20

Cholecalciferol

Answer 20

vitamin D3

Question 21

Which forms of vitamin D are effective in mammals?

Answer 21

D2 and D3

Question 22

Which form of vitamin D is more effective in chicks?

Answer 22

D3 (30x more than D2)

Question 23

Curative method of vit. D testing quality

Answer 23

“line test” based on the observation of epiphyseal cartilage in rats

Question 24

Preventative method of vit. D testing quality

Answer 24

% bone ash in chicks

Question 25

Is there active vitamin D in growing plants?

Answer 25

no

Question 26

Is there active vitamin D in animals?

Answer 26

yes -sunlight on skin (predominant provitamin ---> active cholecalciferol) -by eating sources of vit. D

Question 27

What is the form active in the absorption of Ca in the small intestine?

Answer 27

1,25-(OH)2 cholecalciferol

Question 28

What food sources are rich in vit. D?

Answer 28

-egg (yolks) -liver -fish oils -fishmeals -legumes -leafy alfalfa

Question 29

Vitamin D is not readily secreted in ____

Answer 29

milk

Question 30

Radiant energy activates ______

Answer 30

ergosterol (sun curing of roughages)

Question 31

Is there vit. D in seeds?

Answer 31

practically devoid

Question 32

Effectiveness of sunlight depends on...

Answer 32

-length and intensity of u.v. rays hitting the body -confinement -winter weather -northern areas -long haircoat -aggravated Ca and P ratios -high concentration rations

Question 33

Vitamin D toxicity can lead to ...

Answer 33

hypervitaminosis which leads to hypercalcemia

Question 34

Hypercalcemia

Answer 34

Ca deposits in soft tissues, artery walls, etc. -calcification in pigs if given 1000x the requirement -humans only about 10x the requirement to be toxic

Question 35

Excess vitamin D is used in _______ to cause death

Answer 35

rat poisons