52) IRON ABSOPTION

[Editor]

a) transferrin carries iron in the ferric form
b) Normal faecal loss of iron is 0.1 grams per day
c) Occurs in the ferrous state
d) absorption mainly occurs in the jejunum
e) if reduced produces a microcytic hyperchromic anaemia

[Editor]

TFTFF

Haemoglobin contains 70% of total body iron with myoglobin containing 5%. It is transported in the plasma as transferring which is a Beta 1 globulin carrying iron in its ferric form. Normal daily intake is 10mg although only 10% is absorbed mainly in the duodenum in the ferrous state. Stored iron is in the form of (65%) ferritin and (35%) heamosiderin. Normal faecal loss is in the region of 0.5gramms /day. Lack of iron lead to a microcytic hypochromic anaemia.

[Tonic]

If normal iron intake is 10mg a day and 10% is absorbed with 0.5mg in the faeces what happens to the other 8.5mg?

[drvp]

From the intestinal lumen Fe2+ is absorbed into the intestinal mucosa. The mucosal cells allow some of it to pass into the bloodstream to make up for losses but most of it combines with apoferritin to form ferritin which is stored in the mucosal lining of the intestine. When the mucosal lining is shed, this iron passes with it in the stool. This mechanism prevents an iron overload in the body even if the diet contains excess iron.
If more iron is absorbed than is excreted, iron gets stored in large ferritin and hemosiderin deposits, giving rise to the condition called - Hemochromatosis. This syndrome is characterized by skin pigmentation, ' bronze diabetes ' , liver cirrhosis, gonadal atrophy and increased incidence of hepatic carcinoma.