Week 3: Hematopoiesis

• Erythrocyte

• Leukocyte

• Platelet

• Plasma and serum

• Stem cell theory

• Hemoglobin

• Hematocrit

• Anticoagulant

• EDTA

Blood

• Circulate O2, nutrients, heat, etc.

• Erythrocyte

• Leukocyte

• Platelet (thrombocyte)

• Plasma and serum

Inside of a blood vesselSEM x 2,500

Anticoagulant

• Chelate Ca++ ions• EDTA• Citrate

• Inhibit clotting enzyme• Heparin

• Inhibit glycolysis• Fluoride

Erythrocytes, leukocytes and thrombocytes SEM x1,825

Stem Cell Theory

• Pleuripotential stem cell

• Blast cells

• Differentiation and maturation

• Release into circulation

Recycling Old Cells

• RBCs have 120-day life span

• Reticulo-endothelial system removes old and damaged cells

• Hemoglobin is made of Fe++, porphyrin ring, and globin chains

• Fe++ and globin chains (amino acids) are recycled, but porphyrin ring is eliminated

Red Cell Production

• Oxygen tension

• Level of erythropoietin EPO

• Need for more red cells (during growth, recovering from anemia)

Hemoglobin

• Normal adult Hb A• 2 globin chains

• 2 globin chains

• Heme: porphyrin plus Fe++

• Minor Hb’s• 22: Hb A2

• 22: Hb F

Kinds of Hemoglobin

• Oxyhemoglobin: O2

• Reduced (deoxy-) hemoglobin: no O2

• Methemoglobin: oxidized

• Carboxyhemoglobin: 218 times affinity to CO than O2

• Sulfhemoglobin: sulfa drugs

Hb Problems

• Heme production problem: porphyria

• Fe++ problems: IDA, hemochromatosis

• Globin problem: sickle cell disease, thalassemia

Hb Test

• Reference ranges:• Male 14.0 - 17.0 g%

• Female 12.0 - 15.0 g%

• Cyanomethemoglobin method• Drabkin’s reagent - ferricyanide

• Coulter Hemoglobinometer

Hematocrit

• Reference ranges• Male 42 - 52%• Female36 - 46%

• Packed cell volume

• Modern instruments calculate Hct from RBC and average cell size

Correlation

• Internal QC

Hb x 3 ≈ Hct ± 3