Iron

Question 1

Functions of iron

Answer 1

• Oxygen trasnport - haemoglobin/myoglobin, can bind to oxygen at high conc in lungs and take it to areas of body with low conc.
• Electron transport e.g cytochroms
• Also involed in alot of other reactions as a coenzyme
• energy utilization

Question 2

Process of iron recycling

Answer 2

• Reticuloendothelial cells take up old RBC
• iron is released
• taken up by transferrin –> bone marrow for production of new cells or to liver or spleen for storage
• excess iron stored with ferritin

Question 3

What can accelerate the descritctuin of red blood cells

Answer 3

deficienceys of vit C, E, folic acid, vit B12

Question 4

Iron homeostasis - draw diagram

Answer 4

Erythryocyte prodcution and breakdown
Body stores
Myoglobin respiratory enzymes
Plasma
Daily intake 
Daily loses

Question 5

Iron absorption

Answer 5

Iron from food is absorbed in enetocytes

• mucosal cells in the intestine store excess iron with ferritin
• if body needs iron will be released from ferritin and attached to transferrin to be transported around the body
• If there is to much iron, it is excreted by shedding intestinal cells
• Iron regulatory protein will transport iron into blood and will go around with transferrin protein
• Transferrin receptor on cell (can bind with TF and iron and both get engulfed) to be utilised by cells

Question 6

Iron transport

Answer 6

with transferrin, the transferrin/ transferrin-receptor complex is internalised by cells and iron is released in the cytoplasm

Question 7

What happens in iron deficiencey

Answer 7

cells increas uptake of iron by increasing the expression of transferrin receptors, and decrease ferritin

Question 8

Haem vs non-haem absorption

Answer 8

Haem - is affected only by iron deficiencey (not other foods it is absorbed with)

• haem oxygenase removes haem and so iron is released into cell as Fe2+
• can be absorbed into enterocytes directly
• 25% absorbed
• haem absorbed intact

Non-haem

• 5% absorbed
• must be present in a soluble form to be absorbed
• HCL will make it into soluble form, also dietary reducing agents can reduce/soluble it (things we eat)
• then DMT1 will allow it to be absorbed into cell
• ferric iron is bound to a receptor protein called membrane iron binding protein which transferes iron into the cell (Fe3+ -> Fe2+)
• is affected by composition of meal, inhibitors and enhancers

At basolateral membrane - IREG protein will let iron out, binds to transferrin in blood, ferropoietin
-Also have Transferrin receptors to bind to trasnferrin and are engulfed by cell where iron is released

Question 9

What affects iron absorption in mucosal cells

Answer 9

• size of body stores

- quality of iron in diet

Question 10

Food sources of haem and non-haem iron

Answer 10

Haem - red meat, fish eggs

Non-haem - vegetables, pulses, fortified ceerals, dried fruits

Question 11

enhancers of iron absorption

Answer 11

vit c
MFP factor
organic acids

Question 12

inhibitors of iron absorption

Answer 12

phytates
tannins
calcium

Question 13

factor affecting haem and nonhame iron absorption

Answer 13

haem - iron status of indivudal
-amount of haem iron present

Non-haem - iron status of indiividual

• amount of bioavailable non-ahem iron
• enhancers and inhibitors

Question 14

Who are at risk of iron deficiency

Answer 14

Menstrating women/girls
vegeterians
dedicated athletes
elite female athletes
pregnancy women

Question 15

3 stages of IDA

Answer 15

1. Depleted storage iron (serrum ferritin low)
2. Iron restricted erythropoiesis (serum transferrin saturation low)
3. Iron deficiencey anaemia (haemoglobin low)

Question 16

How is iron vital for growth and development

Answer 16

vital for myelination, neuronal growth and differentiation, neurotransmitter regulation