micronutrients (4.3.4) Flashcards
which micronutriens help in structural function
calcium and phosphorus in bones/ teeth
sulfer in keratin
which micronutrient help in thyroid hormone regulation
iodine (and selenium)
what happens if iodine is inadequate
low T3 and T4 levels leading to excess TSH production, so the thytoid gland enlarges (Goiter)
what is excess iron called
haemochromatosis
where is iron stored
Ferritin protein
name 4 enzymes containing iron and their function
1)Cytochromes: ATP production in mitochondria
2)Cytochrome p-450: detoxification
3)Catalase and peroxidase: prevent free radicals from damaging the cell
4)NADPH dehydrogenase/ any energy metabolism enzymes
which glycoprotein transports iron in the blood
Transferrin
what are the symptoms of iron deficiency/ anemia
skin paleness, shortness of breath, low blood pressure, dizziness, fatigue, fainting
how to assess iron levels
Haemoglobin levels
Serum ferritin
Transferrin saturation
what are the symptoms of zinc deficiency
dwarfism, diarrhoea and hypergonadism
how to assess zinc levels
measure circulating levels in plasma
measure RBCs metallothionein
what is the function of metallothionein
Detoxifies heavy metals (Ca, Pb, Hg) and regulates essential metal ions such as Zn and Cu
what is the function of zinc
involved in nucleic acid synthesis, protein digestion, and protection against free radical formation
neuromodulator
what is the function of bound zinc
stabilizes RNA + DNA structures by “zinc finger motifs”
name 3 enzymes containing selenium and their function
Gluthione peroxidase (GSGPx): protects cell from free radical attack/ ROS
Thoredoxin reductase (TRs): antioxidant and regulates gene expression
Deiodinases (D1, D2, D3): catalyses removal of iodine atoms from thyroid hormones
What are the symptoms of selenium toxicity
Selenosis: Vomiting, diarrhoea, hair and nail loss, lesions of the skin and nervous system
which vitamins are lipid soluble
Vitamin A, D, E, K
What is the function of vitamin A
Visual pigments in the retina (especially in night vision)
what is caused by vitamin A deficiency
night blindness
what is the chemical name for vitamin D
Calciferol
what is the function of vitamin D
Maintainance of calcium levels
what is caused by vitamin D deficiency
Rickets (in children)
oesteoperosis (in adults)
which vitamins are water soluble
Vitamin B1, B2, B3, B6, and B12
what is the chemical name for B9
Folic acid
explain what is caused by B9 deficiency
Megaloblastic anaemia; abnormality in RBC production -> large RBCs
explain what is caused by B12 deficiency
Pernicious anaemia (autoimmune disease); body’s innability to absorb B12
What is the chemical name for vitamin c
Ascorbic acid
explain the function of vitamin C
Vitamin C is an antioxidant. It enhances the absorption of iron by oxidising iron from Fe 3+ (ferric iron) to Fe 2+ (ferrous iron).
Fe 2+ is more easily absorbed
List the steps of vitamin D formation from UV-rays
Skin
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Cholecalciferol (inactive Vitamin D3)
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| Liver hydrolysis cholecalciferol by adding OH at position 25
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25 Hydroxycholecalciferol (1st activation)
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| Kidney hydrolysis 25 Hydroxycholecalciferol by adding OH at position 1
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1,25 Dihydroxycholecalciferol (Calcitriole- actual active form of vitamin D)
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intestinal absorption of calcium via calcium binding protein, calcium stimulating ATPase, and alkaline phosphate
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high plasma calcium concentration
