2. Haematology (RBCs).pdf

By: Ahmed Rashad Mashaal 1. Red cells 2. White cells 3. Platelets 4. Plasma: in which the above elements are suspended.  Plasma is the liquid component of blood that contains soluble fibrinogen.  Serum is what remains after the formation of the fi...

By: Ahmed Rashad Mashaal 1. Red cells 2. White cells 3. Platelets 4. Plasma: in which the above elements are suspended.  Plasma is the liquid component of blood that contains soluble fibrinogen.  Serum is what remains after the formation of the fibrin clot.  RBCs are rounded, biconcave, non- nucleated discs.  They are not true cells (no nuclei, organelles, nor cytoplasm). RBCS contain mainly haemoglobin.  They are formed in the bone marrow and destroyed in the reticulo- endothelial system.  The life span is about 120 days.  Haemoglobin performs the main functions of red cells- carrying oxygen from the lungs to the tissues and returning CO2 from the tissues to the lungs.  Haemoglobin consists of : Haem + Haemoglobin globin ( 4 polypeptide chains).  Haem consists of: Iron + Haem Globin protoporphyrin. (four polypeptide chains)  the pigment (proto-porphyrin) is excreted in bile as bilirubin. Iron Protoporphyrin (ferrous atom)  Adult haemoglobin ( Hb A) consists of 2alfa and 2Beta globin chains.  A haem group is bound to each globin chain.  The haem group has a porphyrin ring with a ferrous atom which can reversibly bind one oxygen molecule.  Each molecule of Hb carries 4 molecules of oxygen.  Hb A: 2alpha & 2 beta chains comprises 97% of Hb in adults.  Hb A2: 2alpha & 2 delta chains comprises 1-2% of Hb in adults.  Hb F : 2alpha & 2 gamma chains comprises 1% of Hb in adults.  Haemoglobin concentration: male 13.5 - 17.5 gm/dl female 12 - 16 gm/dl  Red cell count: male 4.5 - 6.0 million/cmm female 4 - 5.5 million/cmm  Haematocrit or packed cell volume (PCV): Definition: It is the volume of packed red cells in 100-ml blood. Normal level: 40-52% in male 36- 48% in females.  A) Mean cell volume (MCV)  Normal value= 80-100 fl.  In anaemia:  If MCV is decreased (100)  Macrocytic anaemia.  B) Mean cell haemoglobin (MCH):  Normal value= 27-34 pg.  In anaemia:  If MCH is decreased (