Figure 8.

Effects induced by varying kidney sensitivity k on the equilibrium curves and bifurcations with respect to lead intake p. Equilibirum curves with respect to lead intake p are shown, for two values of kidney sensitivity: lower sensitivity $k=0.05$ (blue curves) and higher sensitivity $k=0.5$ (red curves). Each panel shows a different projection of the same two equilibrium curves. We chose to illustrate the kidneys components K_Pb and K_Ca, since they are most likely to be affected, and the brain components B_Pb and B_Ca, since they are the primary object of our study. The other system parameters are fixed, as before, to: $c=10$, $z=1$, $s=1$, $B=0.8$, $\theta =6$, $\tau =4$, $a=b=0.6$.