Mentoring and coaching are related disciplines. While a coach is a person who knows the mechanisms of change and guides you to the goal, regardless of whether he is an expert in the field you work in, a mentor is a person who has the experience, skills, and knowledge to lead you to the desired goal. Mentoring can be a long-term process of your professional learning and development, while coaching is a more focused process that is limited in time.
With a good mentor, professional development is much faster and more efficient.