This work deals with the effects of defects and exposure to electromagnetic field on the generation and propagation of action potential in a single nerve fibre. After a physical and mathematical modelling of nerve fibre defects and exposure to EMF, appropriate mathematical and numerical methods are used to investigate the action of each phenomenon on the generation and propagation of front waves. It is found that defect in myelin sheath and imperfections of ionic channels strongly modify the velocity of propagation and can even lead to propagation failure. The domain of initial values of the amplitude and width of the signal or excitation leading to front waves generation are delineated for each type of perturbation. This domain increases or decreases due to perturbations.