Erythrocytes aka RBC’s. Laboratory Procedures. What is Blood?. Whole Blood = fluid and cells Fluid Component = PLASMA Cellular Component Erythrocytes (RBC) Leukocytes (WBC) Thrombocytes (Platelets). How Are These Cells Produced?.
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Whole Blood = fluid and cells
FluidComponent = PLASMA
Hematopoesis : the production of blood cells and platelets.
Erythropoesis : the production of erythrocytes (RBC)
In juveniles, blood produced in liver, spleen, thymus and bone marrow.
In adults, primary site of erythropoesis is in the bone marrow.
During times of hematopoetic stress, the slpeen and liver may produce RBC
Thrombopoiesis : the production of thrombocytes or platelets
Proteins called Cytokines are responsible in determining the fate of all stem cells.
Erythroblasts – Erythrocytes (Erythropoietin)
Myeloblasts –Leukocytes / Monocytes
Separates into three components:
Red Blood Cells (RBC’s)
White Blood Cells and platelets (buffy coat)
Bottom 1/3 to ½ of tube contains the heaviest of cellular material (the RBC’s).
To determine hematocrit, whole blood is centrifuged to pellet the red blood cells.
Plasma remains on the top of the red cells.
The fraction of blood that is packed is the hematocrit and is read as a percentage.
Normal values are usually 1/3 of the hematocrit.
Each hemoglobin molecule has 4 heme units attached to globulins.
Abnormal heme groups, cannot carry oxygen.
Carboxyhemaglobin- Hgb has a higher affinity for CO than O2.
Bright red blood
Methemoglobin- The Fe molecule is oxidized to Fe+3.
Blood becomes brown.
Tylenol toxicity in cats.
Carry oxygen to the tissues
Oxygen must be carried at enough pressure to permit rapid diffusion of oxygen.
The RBC is a vehicle for hemoglobin which is the carrier molecule for oxygen.
The sigmoid shape of curve is a result of the cooperative binding from the 4 hemoglobin molecules.
The morphological features of mature red blood cells of dogs, cats, horses, and ruminants are generally very similar in that they all lack nuclei, stain reddish to reddish-orange.
Erythrocytes are biconcave discoid-shaped cells.
The major differences are in the size of the red blood cells and the degree of central pallor.
Listed from largest to smallest in size are :
Maturation of a RBC.
Only occurs in the bone marrow of normal adult animals.
Occurs in the spleen and liver of the fetus.
Maturation time usually takes 5 days.
Regulated by erythropoietin (EPO) which is increased in the presence of hypoxia.
In most species, the kidney is the sensor organ and major site of EPO.
No nucleus due to have to fold and squeeze through tight spaces.
Normocytes- cells look normal
Dog- 110 days
Cat- 70 days
Cow- 160 days
Horse- 145 days
Man- 120 days
Mouse- 30 days
Stem Cell → Rubriblast → Prorubricyte → Metarubricyte → Rubricyte → Reticulocyte → RBC
Rubricyte- nucleated RBC releases in severe anemia.
No more mitotic division takes place after this stage.
1. Cell arrangement on the blood film.
5. Presence of structures on erythrocytes
Can be a normal occurence!!
Most Commonly Seen in Horses!!!
Usually associated with iron deficiency.
Especially in Llamas
Also known as poikilocytes.
RBC’s with abnormal shape.
Formed as a result of shearing of the cell by fibrin strands. This occurs when red blood cells rapidly pass through microvasculature that is lined or meshed with strands.
They are observed in fragmentation hemolysis caused by DIC, vascular neoplasia, endocarditis, and possibly iron deficiency anemia.
Identified as the presence of many irregular membrane projections involving most RBC’s.
It is usually an artifact due to slow drying of the blood film.
Commonly observed in pig blood but can be seen in any species.
Cells have a spheroid shape instead of the usual biconcave disk shape.
Have reduced cell membrane and are hypochromatic.
Seen most frequently in autoimmune hemolytic anemia (AIHA). When WBC partially remove antibody-coated membranes.
Usually seen in dogs.
Two types of cells observed mainly in dogs.
Represent cells with an outfolding of the rbc membrane.
The cell membrane is thin and flimsy.
Can be associated with liver dz and reticulocytosis.
artifacts when smears
made in high humidity
or if blown dry.
Can indicate liver disease or hemoglobinopathies.
Nuclear remnants observed in young erythrocytes.
Often observed in cats and horses.
Can be seen in regenerative anemic animals.
Also may be seen with splenic disease or in an animal with the spleen removed.
Metarubricytes are sometimes found in the peripheral blood.
Usually observed with regenerative anemias.
May be found in non-regenerative states such as lead poisoning and hypoxia.
Observed in RBC’s that contain abnormal aggregation of RNA.
Can be observed in cases of heavy metal poisoning with non-regenerative anemias or intense erythrogenesis in dogs, cats, and ruminants.
Particles of denature hemoglobin protien.
They stain with new methylene blue and appear as colorless bumps with quick stain.
May be caused by oxidant drugs and chemicals.
Normal cat blood may have 2-3%.
Spleen recognizes as abnormal and starts to lyse the cells.
Non-nucleated cell containing RNA which can be easily seen when stained with methylene blue.
Hallmark of erythrocyte regenerative response.