Brain and sensory organs 

The brain is the centre of the nervous system and together with the spinal cord forms the central nervous system. The sensory organs are the parts of the nervous system that receive external stimuli, which are then transmitted to the brain. Diseases of the nervous system fall under the umbrella of neurology, with specialisations such as neurosurgery, neuromodulation and neurorehabilitation, among others. Sight disorders are treated in ophthalmology and hearing disorders in otolaryngology and audiology. 

Tumours and immunology 

Tumours are diseases resulting from the unrestrained division of cells through mutations occurring in them, the loss of repair mechanisms and, consequently, the loss of control by the organism over the natural cell cycle of division and apoptosis (cell death). Cancer is treated by oncology, an interdisciplinary field of medicine that uses various treatment methods, including radiotherapy, chemotherapy and surgery. Haematology is the field of cancerous and non-cancerous diseases of the blood and haematopoietic system. Immunology studies the reactions of the immune system responsible for the body's defense reactions against pathogens or other foreign substances and bodies.  

Cardiovascular diseases 
Cardiology specialises in diseases of the heart and vessels (the cardiovascular system). It deals with the entire cardiovascular system and cardiovascular diseases, including hypertension, which is diagnosed and treated by hypertensiology. Cardiac surgery is responsible for the surgical treatment of the heart and vascular diseases, while angiology and vascular surgery deal with vascular diseases. The most commonly diagnosed cardiac disorder is coronary heart disease or ischaemic heart disease. 

Organ surgery and transplantation, reconstructive and regenerative medicine 

Surgery is the branch of medicine involved in surgical treatment. It involves procedures relating to pathologies arising in the course of injuries, dysfunctions and diseases of organs. Due to its broad scope and subject matter, it intertwines with many other fields of medicine, e.g. musculoskeletal surgery is part of orthopaedics and surgery of the nervous system is part of neurology. Plastic (reconstructive and aesthetic) surgery deals with the reconstruction of body defects and the correction of their real or perceived appearance. In organ transplant surgery, known as transplantology, it is not only important to implant a new organ skillfully, but also to prevent its rejection by the recipient's organism, which is closely related to immunology.  

Communicable diseases 

Communicable diseases are caused by infectious agents: bacteria, viruses, prions or fungi. As a result of their activity, the body's immune strength is compromised. Treatment for infectious diseases is usually causal, aimed at inhibiting pathogenic microorganisms and inactivating toxins of biological origin. Microbiology, especially its branches — bacteriology, mycology and virology — is the study of microorganisms causing these diseases. Vaccination is an effective protection against many infectious diseases; vaccinology deals with research on vaccines.  

Paediatric medicine 

Paediatric medicine is a separate branch of medicine, which stems from the discovery that a child is not a "small adult". The differences in body structure, physiology and the occurrence of defects and diseases affecting only children and adolescents as well as the different course of many diseases justify its separate management. This is particularly important in paediatric surgery, where anatomical, physiological and metabolic differences are important. Paediatrics deals with paediatric diseases and the care and development of healthy children, whereas diseases of the prenatal and neonatal period fall within the scope of neonatology.