Vitamins And Liver As A Storage Organ Flashcards
What happens to iron after absorption?
It is absorbed in the duodenum and then transferred by plasma transferrin either to be used in the muscle as myoglobin or in RBCs as haemoglobin.
If it is not used it can be stored in the liver or in reticuloendothelial macrophages.
What is ferritin?
Function?
Large protein consisting of 24 linked subunits that from a shell around a central core.
The core contains up to 5000 atoms of iron.
Found in cytoplasm of cells and serum
Conc directly proportional to total iron stores
Used to measure iron in body
Function = how iron is stored in the liver
Ferritin excess issues:
Store too much ferritin =
haemochromatosis - genetic
Haemolytic anaemia
Liver disease - can cause ferritin increase even tho iron conc not increased
Why do mails show earlier hemochromatosis than females - usually in 50s?
Signs:
This is because females have a way of removing iron through periods.
Tired all the time
High iron and ferris conc of blood
Genetic test to confirm it
Treatment = removal of blood - gene puncture
What are the two main categories of vitamins?
What does this result in?
Water soluble and fat soluble
Water soluble vitamins pass more readily through the body and the fire require more of a regular uptake than fat soluble vitamins which can be stored
Vitamins A:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
Retinoids
Fat soluble - stored
From retinols - eggs, meat
Or carotenoids - carrots, tomatoes
RDA - 0.6 mg/day
Function = used to form rhodopsin in rod cells in the retina
Spermatogenesis
Deficiency may occur due to feat malabsorption
- night blindness, blindness
Excess - acute abdominal pain, nausea, headaches
Chronic - joint and bone pain, hair loss, anorexia, carotenemia - just oranging of the skin for a while
Vitamins D:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
None
Fat soluble
Sun, fish, meat
Note darker skin decreased vitamin D from sun
—
Increase intestinal absorption of calcium
Formation of bind
Reduced renal excretion of calcium
Deficiency = demineralisation of bone — rickets in children osteomalacia in adults
Too much vitamin D toxicity — hypercalceamia — metastatic calcification
Vitamins E:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
—
Fat soluble - stored in adipocytes and also liver
Spinach, avocado, carrots
4mg/day
Deficiency - like all may be due to fat malabsorption
Lead to - haemolytic anaemia
Excess = safe
Vitamins K:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
—
Fat soluble — K1 — K4
Spinach, broccoli
—
Activation of some clotting factors - liver synthesis of II, VII, IX, X
Deficiency = haemorrhagic disease of newborn
Rare in adults unless on warfarin
Excess - safe if natural
Note it is transported by lipoproteins in the plasma
Vitamins C:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
—
Water soluble
Fresh fruit and veg
Need 40mg/day
Collagen synthesis, antioxidant, iron absorption
Deficiency = scurvy - easy bruising and bleeding, teeth and gum disease
Excess = a lot can lead to GI side affects
Vitamins B12:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
Cobalamins
Water soluble
Meat, fish eggs, milk
—
Deficiency = may be due to autoimmune destruction of IF producing cells
Veganism
Anaemia - as important in RBC production
—
Note - it is realised from food by acid in the stomach. Intrinsic factor pricked by stomach forms a complex with B12 and this aids its absorption in the terminal ileum
Then stored in liver
Folate:
Other name
Type
Sources
RDA
Function
Deficiency
Excess
—
Water soluble
Found in mainly foods fortified with folic acid, cereal
—
Functions as a coenzyme in methylation reactions, DNA synthesis etc
Deficiency -
May be caused by malnutrition or drugs that interfere with folic acid metabolism
Lead to -
Anaemia, foetal developments abnormalities (neutral tube defects)
Where are clotting factors produced?
In the liver:
I (fibrinogen)
II prothrombin
IV
V
VI
VII
How can the performance of clotting factors be measured?
Prothrombin time (extrinsic pathway)
May signal a deficiency in the synthetic capacity of the liver, liver disease, drugs, vitamin K deficiency
aPTT - intrinsic pathway test
