Figure 7.

Contour plots of stretch rate $\dot{\lambda }$, effective viscosity ${\eta }^{\text{eff}}$, passive viscosity ${\eta }^{\text{pass}}$, and force through the microtubule system $F_{\text{MT}}^{\text{e}}$, as a function of the total number of myosin and dynein proteins and for different values of $F^{\text{ext}}$ in our analytical model. The stretch rate and viscosity contour plots show good agreement with the computational results in Fig. 6, which confirms that the analytical model captures the physics of the computational model. The forces through the microtubules system, $F_{\text{MT}}^{\text{e}}$, become more compressive for high numbers of dynein proteins because of the additional extensile force generation that pushes the growth cone forward. Increasing the number of myosin proteins reduces the stretch rate of the axon because of the contractile forces generated by myosin. To view this figure in color, go online.