The study or dealing with…

Cancers
Oncology
The aging process
Gerontology
Diseases and the changes they cause
Pathology
Heart diseases
Cardiology
Pregnancy and birth
Obstetrics
Factors determining the frequency of health related conditions
Epidemiology
Children and their diseases
Pediatrics
Body’s resistance to infectious diseases
Immunology
Skin and its diseases
Dermatology
Nervous system and its disorders
Neurology
Drugs and their uses in treatment of diseases
Pharmacology
Muscular and skeletal system problems
Orthopedics
Poisonous substances
Toxicology
Xrays and radioactive substances
Radiology
Blood and blood diseases
Hematology
Cells
Cytology
Hormones and hormone secreting glands
Endocrinology
Female reproductive system
Gynecology
Eye and eye diseases
Opthalmology
Care and treatment of the feet
Podiatry
Ears, nose and throat specialist
Otolaryngology
Diseases and disorders relating to the kidney
Nephrology
Diagnosis and treatment of disorders of the colon, rectum or anus
Proctology
Urinary tract and organs of the urogenital system
Urology
Specifically deals in the drawing of blood
Phlebotomy
Mental Health
Psychiatry