This thesis deals with the effects of defects and exposure electromagnetic field (EMF) on the generation and propagation of action potential in nerve fibre. After a good 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, imperfections of ionic channels and exposure to EMF can even lead to propagation failure, increase or decrease the domain of action potential generation.