Key Terms
Layers from bottom to top after centrifuge
1. Erythrocytes (bottom, heaviest) 2.
Other plasma solutes
Electrolytes (sodium, potassium, calcium), dissolved gases (O2, CO2, nitrogen), glucose, amino acids, vitamins, lipids,
Hemopoiesis (hematopoiesis)
The process of producing formed elements. Occurs in red bone marrow.
Extramedullary hemopoiesis
Production occurring outside the bone marrow (liver and spleen retain this backup capacity; activated in disease states
Shape
Biconcave disk (thick at edges, thin in center)
Reticulocytes
Immature erythrocytes; still contain remnants of organelles. Should be 1-2% of RBC count.
Structure
4 globin protein chains (alpha 1, alpha 2, beta 1, beta 2); each globin is bound to a heme group; each heme contains one
Oxygen binding
Each iron ion binds one O2 molecule; one hemoglobin molecule carries 4 oxygen molecules; one RBC contains ~300 million h
Production rate
Over 2 million cells per second in bone marrow
Lifespan
Up to 120 days
Destruction
Macrophages in bone marrow, liver, and spleen phagocytize worn-out RBCs
Anemia
Deficiency of RBCs or hemoglobin; results in reduced oxygen delivery; symptoms include fatigue, headache, shortness of b
Three major causes
1. Blood loss (wounds, ulcers, hemorrhoids, excessive menstruation, GI cancers, NSAID overuse) 2.
Polycythemia
Elevated RBC count; increases blood viscosity; harder for heart to pump; can be caused by dehydration, high altitude ada
Production
Thrombopoietin (from liver and kidneys) stimulates megakaryoblasts to mature; each megakaryocyte releases 2,000-3,000 pl