Audiologist specialized in ear related issues
allergist work in any variety of patients suffers from any allergies etc
anesthesiologist study the effects and reactions to anesthetic medicines
cardiologist specify in the study and treatment of the heart
immunologist study the immune system in a variety of organisms
microbiologist study the growth infectious bacteria and viruses
neonatologist care for newborn infants
physiologist study the states of human body including emotional and needs
podiatrist studies ailment that afflict the feet and ankles