Vitamin D Flashcards
Vitamin D is fat soluble….True or Flase?
True
Name the 2 forms of vitamin D
D2, D3
Where is Vitamin D3 (cholecalciferol) made?
In the skin
Where do you find vitamin D2 made (ergocalcifero)?
Plants
Parathyroid hormone secreted by the parathyroid glands in response to a low concentration of __________ in the blood
Calcium
Vitamin D3 is converted in the kidneys…True or False?
False, it is converted in the liver
What is the prehormone of Vitamin D3?
25-hydroxy vitamin D (calcidiol)
What happens in the kidney to 25-dihydroxy vitamin D (calcitriol)
It acts like steroid hormone
Vitamin D is also a secosteroid hormone? True or False
True
What is vitamin D responsible for?
Maintaining a normal concentration of calcium and phosphate in the blood
Name a few things Vitamin D, Calcium and phosphate in the blood are responsible for….?
- Mineralisation of bone
- Muscle contraction
- Nerve conduction
- General cellular function, there are receptors for calcitrol in 30 tissues in the body
- Possible regulation of over 1000 genes
- calcium regulating hormone, a secosteroid
- Regulates transcription of cell proteins in: osteoclasts (bone resorption) enterocytes (gut wall cells) and keratinocytes (skin)
Who is at risk of deficiency?
- Infants
- Adolescents
- Pregnant women
- Elderly
- Vegetarians
- Those not exposed regularly to sunlight, esp in high latitudes
- People with dark skin at high latitudes
How many minutes of UV exposure will meet your daily Vitamin D needs?
About 30 min exposure of face and arms if living between 42° N and 42° S
What can affect the amount of Vitamin D you are exposed to?
- Latitude and season
- Age: skin thins in the elderly, so less effective
- Skin pigmentation: dark skin protective, but not in high latitudes
- Clothing: degree of coverage and thickness
- Use of sunscreen
Rickets, Osteomalacia, Osteoporosis and all what forms of what?
Vitamin D deficiency diseases
