Primary Care Physician is a physician /medical doctor who provides both the first contact with an undiagnosed health concerns as well as a continuing medical care of various medical conditions, not limited by cause, organ system or diagnosis.
Your primary care doctor also coordinates care between your different specialists. For example if your Cardiologist gives you a medicine for irregular heart beat your PCP will monitor you for possible side effects, some might effect your thyroid gland which can be managed by your PCP or if needed he or she will refer you to an Endocrinologist (Endocrine glands specialist) .