Internal medicine is the largest specialty in medicine. It covers diseases of lungs, heart, gastrointestinal tract, genitourinary system, rheumatic diseases. The human body is a indivisible whole, and all organs and systemic function in continuous interaction. Physicians - internists perform a thorough examination of the patient, diagnose and treat the disease. Additional examinations are prescribed when is necessary. Due to its largeness internal medicine specialty is subdivided a number of narrow specialties, gastroenterology, pulmonology, etc.