Iron deficiency anaemia Flashcards
What is the average lifespan for a RBC?
120 days
What is the average lifespan for platelets?
7-9 days
What is polycythaemia?
High increase in RBC production
What is the normal levels of haemoglobin in males and females?
Men - 150g/L
Women - 135g/L
What reference range of haemoglobin would one have who is deemed to be anaemic?
<105pg/L
What is IDA caused by?
A lack of iron available to produce Hb, causing the cells to be microcytic and hypochromic
What makes up haemoglobin?
In an adult - 2 alpha and 2 beta polypeptide chains
In a foetus - 2 alpha and 2 gamma chains
What is most of the iron in the body recycled by?
The reticuloendothelial system
What are the 2 states iron exists in?
Fe3+ (ferric) and Fe2+ (ferrous), ferric is insoluble
Why is there very little amounts of free iron in the body?
Because free iron is toxic, causes profound effects on brain function and can cause the heart rate to go above 100bpm (tachycardia)
What type of iron is most easily absorbed?
haem iron, primarily in red meats
How is iron regulated in the body? (long answer)
As there is no physiological mechanism for regulating iron elimination, iron absorption is a very important role. As iron passes through the duodenum it is brought into the enterocytes via active transport by the protein DMT-1. Once inside the cell, the iron can be bound in the cell as ferritin, bound specifically to apoferritin, which will be stored inside the enterocyte. Alternatively, it can be pass through iron channels via ferroportin and enter the bloodstream to be rapidly bound by apo-transferrin and taken to red blood cell precursors, which take up the iron via receptor-mediated endocytosis.
What is hepcidin?
Hepcidin is an iron-regulating hormone that inhibits ferroportins, causing iron to remain inside enterocytes
Can iron be stored anywhere besides enterocytes?
Yes, In the blood bound to transferrins they can be taken to sites of storage such as the liver in hepatocytes or can be stored in the bone marrow
What is haemoglobin converted into following senescent RBC destruction?
Senescent RBC are ingested by macrophages, which are degraded by hydrolytic enzymes to release the haemoglobin that can be converted into bilirubin