Chapter 9 Vitamin

Question 1

Vitamin A function

Answer 1

1. maintenance of normal vision
2. regulates of cell growth and differentiation
3. Regulates lipid metabolism
4. Maintains resistance to infection

Question 2

Vitamin A defiency causes

Answer 2

1. Night blindness, xerophthalmia (Dry eye), and blindness
2. Respiratory squamous metaplasia and keratinization: xeropthalamia => bitot spots (build up of keratin) => kertomalacia (destroys cornea)
3. Fat malabsorption => cystic fibrosis
4. Vulnerable to infections (particularly measles) d

Question 3

What is the transport and storage form of vit A?

Answer 3

retinol

Question 4

Acute vit A toxicity:

Answer 4

HA, dizziness, V, stupor, blurred vision,

Question 5

Chronic vit A toxicity

Answer 5

weight loss
anorexia
NV
Bone and joint pain

Question 6

Vit D function

Answer 6

1. Absorbs Ca2+ in the intestine and phosphorus
2. Mineralization of bone
3. Neuromuscular transmission

Question 7

Vit D deficiency causes

Answer 7

1. Rickets in kids, if epiphysis has not closed
2. Osteomalacia in adults

not neough exposure to sunlight?

3. hypocalcemia tetany

Question 8

Children with Rickets display

Answer 8

Poor formation of bones causes:

Head: frontal bossing and squared head

Chest: rachitic rosary, pigeon breast,

Other: lumbar lordosis and bowing of legs

Question 9

What is rachitic rosary

Answer 9

Vit D deficiency causes a deformation of the chest that is d/t cartilage overgrowth at the costo-chondral junction

Question 10

What is osteomalacia

Answer 10

bones do not mineralize and they are weak => more liekly to fracture

Question 11

What is the major source of vitamin D?

Answer 11

Endogenous synthesis from a precursror [7-dehydrocholesterol]
in the skin/ingested in a photochemical reaction that requires sun or artitificial UV light

Question 12

PRogression of developtment of active vitamin D

Answer 12

1. 7-dehydrocholesterol => 25(OH)D in the liver

2. => 1,25(OH)2D in the kidney, its active form (1, 25-dihydroxyvitaminD)

Question 13

How does (1, 25-dihydroxyvitaminD) cause absorption of CA2+ and phosphorus in the intestine?

Answer 13

+ expression of RANKL.

Question 14

Vit D def causes a decrease of absorption of Ca2+ and phosphorus in gut => decreased levels in blood. What then happens?

Answer 14

1. Parathyroid glands + => release PTH => breaking up Ca2+ and phosphorus from bone; phosphate is lost in urine but calcium is retained => serum Ca2+ levels is near NL but phosphate is low => mineralization is impaired.

Question 15

Vit C function (water soluble)

Answer 15

Important in:

1. redox reactions
2. Hydroxylation (Crosslink) of collagen

Question 16

Vit C deficiencies

Answer 16

Scurvy => impaired collagen crosslinking

Question 17

What is scurvy

Answer 17

Vit C def => bone disease in growing kids and a causes hemorrhages and healing problems in kids and ADULTS d/t poor cross linking of collagen

Question 18

How do we get vit C

Answer 18

not made by the body; thus we depend on it from diet

Question 19

Vit K function

Answer 19

cofactor for factors 2, 7 , 9 and 10, protein C and S

Question 20

Vit K def

Answer 20

Bleeding diathesis (hypercoagulable)

Question 21

Vit B1 function (thiamine)

Answer 21

coenzyme in decarboxylation reactions

Question 22

Vit B1 def

Answer 22

Dry and wet beriberi,
wernicke syndrome,
korsakoffe

Question 23

B3 Niacin function

Answer 23

make NAD and NADP; redox reacions

Question 24

B3 Niacin def

Answer 24

Pelligra: 3 D’s; demntia, dermitis and diarrhea

Question 25

B2 (ribloflavin) fx

Answer 25

make FAD and FADH; cofactors for intermediate metabolism

Question 26

B2 (ribloflavin) def

Answer 26

ariboflavinosis, cheilosis, stomatitis, glossitis, dermatitis, corneal vascularization

Question 27

B6 (pyrixodine) fx

Answer 27

coenzyme in many intermediary reactions

Question 28

B6 def

Answer 28

maintains myelination of SC tracts

cheilosis, glossitis, dermatitis, peripheral neuropathy