Vitamin D

Question 0

What is Vit D comprised of?

Answer 0

Ergocalciferol and cholecalciferol

Question 1

What type of hormone is vit d?

Answer 1

Steroid hormone

Question 2

What is the precursor and how is it retrieved?

Answer 2

7-dehydrocholesterol

Ingested in food or synthesised in skin

Question 3

What happens to the precursor to turn it into vit D?

Answer 3

Hydodxylated in liver (at C25) and in kidney (at C1)

Question 4

What is the active form of Vit D?

Answer 4

1,25-(OH)2- cholecalciferol

Question 5

What type of receptor?

Answer 5

Nuclear receptors (steroid-like)

Question 6

3 roles of Vit D?

Answer 6

Increases gut calcium absorption
Makes osteoblasts produce a factor which stimulates osteoclasts-> increases bone reabsorption of calcium
Reduces PTH transcription from parathyroid gland

Question 7

Calcium is important for

Answer 7

Bone formation and remodelling
Intercellular signalling
Secretion
Excitation and contraction coupling
Cofactors in enzyme function

Question 8

Deficiency causes what?

Answer 8

Children- rickets

Adults- osteomalacia

Question 9

Symptoms of Vit D deficiency

Answer 9

Soft bones, bone pain, muscle weakness, bending of bones, easy fracturing

Question 10

Causes of Vit D deficiency

Answer 10

Lack of sunlight, diet, renal tubercular acidosis, malabsorption, coeliac disease

Question 11

Transported in blood bound to

Answer 11

Transcalciferin (a globulin)