Iron Flashcards
Ferritin
Large spherical protein
24 non-covalently linked subunits
Core contains up to 5000 iron atoms
Found in cytoplasm and in serum
Concentration of ferritin directly proportional to total iron stores in body
Ferritin excess
Several disorders such as hereditary haemochromatosis, multiple transfusions, iron replacement therapy.
Ferritin deficiency
Only known cause is iron deficiency.
Can result in anaemia
Iron usage and storage
Used in muscles and bone marrow.
Stored in liver parenchyma and reticuloendothelial.
Lost through sloughed mucosal cells, desquamation, menstruation
Importance of vitamins
Acts as gene activators, free-radical scavengers, co-enzymes and cofactors of metabolic reactions.
Are vitamins B and C water soluble?
Yes
Pass more readily through body so more regular intake needed than fat-soluble vitamins
Which vitamins are fat soluble?
A, D, E and K
Vitamin A (retinoids) sources
Directly from meat or produce retinal from carotenes.
Retinols = Eggs, cereal, dairy, cheese, liver
Carotenoids = carrots, spinach, tomato, sweet potato
Vitamin A Functions
Vision - to form rhodopsin in rod cells
Reproduction - spermatogenesis in male, prevention of foetal resorption of female
Growth
Stabilisation of cellular membranes
Vitamin A deficiency symptoms
Night blindness, xeropthalmia (damage eyes), blindness
Vitamin A excess
Acute:
abdominal pain, nausea, vomiting, severe headaches, dizziness, sluggishness, desquamation of skin
Chronic:
Joint and bone pain, hair loss, dry lips, weight loss
Carotenemia:
Reversible yellowing of skin
Vitamin D Functions
More calcium absorption, less calcium excretion, formation of bone
Vitamin D deficiency
Demineralisation of bone (rickets in children, osteomalacia in adults)
Vitamin E Storage
non-adipose cells such as liver and plasma and adipose cells
Vitamin E Deficiency
Caused by fat malaborption (cystic fibrosis), premature infants, rare congenital dfects in fat metabolism
Symptoms = haemolytic anaemia, myopathy, retinopathy, ataxia (poor muscle control), neuropathy
Excess is relatively safe
Vitamin K take up
Rapidly taken up by liver, transferred to very low and low density lipoproteins which carry it into plasma
Vitamin K sources
K1 is synthesised by plants
K2 is synthesised by intestinal bacteria
Vitamin K functions
Responsible for activation of some blood clotting factors.
Needed for liver synthesis of plasma clotting factors II, VII, IX and X.
Vitamin C sources
Fresh fruit and veg, citrus
Vitamin C functions
Collagen synthesis, antioxidant, iron absorption
Vitamin C deficiency
Scurvy, easy bruising and bleeding, teeth and gum disease, hair loss.
Vitamin C excess
Can cause GI side effects
Vitamin B12 sources
Released from food by acid and enzymes in stomach. R protein protects from stomach acid. Pancreatic polypeptide releases it from R proteins. Intrinsic factor produced by stomach
Vitamin B 12 storage
Liver
B12 deficiency
No intrinsic factor means no B12 absorption, veganism, malabsorption (lack of stomach acid, pancreatic disease)
Symptoms = macrocytic anaemia
Peripheral neuropathy in prolonged deficiency
Folate
Found in food with fortified folic acid. Higher requirements in pregnancy.
Co-enzyme in methylation reactions, DNA synthesis, synthesis of methionine from homocysteine.
Folate deficiency
Malabsorption
Drugs interfering with folic acid metabolism
Disease states that increase cell turnover (psoriasis, leukaemia)
Symptoms:
high homocysteine levels (damage arterial walls), macrocytic anaemia (large blood cells), foetal development abnormalities (eg. neural tube defects)
Clotting factors
Intrinsic pathway is activated by…
Contact
Clotting factors
Extrinsic pathway is activated by…
FVII coming in contact with tissue factor
Cascade results in fibrin clot formation
Where are clotting factors produced?
The liver (I, II, IV, V, VI, VII)
How can clotting factors be measured
Prothrombin time
International normalised ratio
Activated partial thromboplastin time
