Fig. 2.
A diagrammatic representation of the relationships between stem cells and neutrophils. Resting G0 phase stem cells (S) may either stay in that phase indefinitely, re-enter the proliferative phase at a rate K(S) dependent on S or differentiate into the neutrophil line at a rate F (N) where N is the circulating number of mature neutrophils. (Differentiation into the erythrocyte and platelet lines is neglected in this treatment, but it is unimportant for the considerations here.) Following differentiation into the neutrophil line, a stem cell undergoes an amplification (box with a peak) A during a maturation period lasting τN days before being released into the circulation (bottom circle) as a mature neutrophil and dying at a random rate α. Taken from Bernard et al (2003) with permission.