Red Cell Structure and Function Flashcards
Describe the cell lineage in the development of RBCs?
Haemapoietic stem cells
- > Pronormoblast
- > Normoblasts
- > Reticulocytes
What is a pronormoblast?
the earliest line-commited progenitor cell
What stimulates the pronormoblast differentiation?
EPO
What are normoblasts?
Where the pronormoblast is filled with haemoglobin
What are reticulocytes?
Immature RBCs whose nuclei havn’t yet atophied
What is required for the production of RBCs?
Progenitors (requires stem cells, EPO, other factors)
Haemoglobin (Requires Fe and normal Hb synthesis)
DNA production
Normal protein/membrane synthesis
What is the effect on RBCs if haemoglobin deficiency?
Microcytic anaemia
What is the effect on RBCs of folate and B12 deficiency?
Macrocytic anaemia
- since B12 and folate responsible for DNA synthesis, th. not enough DNA for regular mitoses
Describe antigen manufacture related to the ABO blood system
Antigens have common precusor protein H which has sugar residues added to it by enzymes to create an antigen
- no sugar => non-antigenic => O group
- A-sugar => A antigen => A group
- B-sugar => B antigen => B group
What antibodies occur in blood group A?
Anti-B Antibodies, i.e. Anti-B IgM
What antibodies occur in blood group B?
Anti-A antibodies, i.e. Anti-A IgM
When do antibodies attack red blood cells?
When the RBCs display foreign antigens
- causes cell lysis (via completement and MAC)
- causes wider immune reaction
What are anti-D antibodies?
Anti-D antibodies (Anti-D IgG) form (not naturally present) when exposed to Rhesus D antigen in Rhesus -ve patient
How may exposure to Rh D antigen occur in rhesus -ve patients?
Via:
- transfusion
- labour = foetus may be rhesus +ve th. mother develops anti-D anitbodies to foetus blood
Describe transfusion reactions to Rh +ve blood in Rh -ve mothers
Immediate reaction = if mother has previously been exposed to Anti-D IgG
Delayed reaction = if pt. develops anti-D IgG (hrs/days later)
