Pathology is a basic medical science that studies the causes, mechanisms, development patterns of human diseases, as well as the morphological structure, functional metabolic changes and lesion outcomes of the body during the disease process.

Pathology has always been regarded as a "bridge discipline" between basic medicine and medicine, fully demonstrating its irreplaceable and significant role in medicine, which is determined by the nature and tasks of pathology.

Disease is an extremely complex process. Under the interaction of pathogenic factors and the body's response functions, various changes will occur in the morphological structure, metabolism and function of the relevant parts of the diseased body, which is an important basis for the study and understanding of diseases. The task of pathology is to use various methods to study the causes of disease (etiology), the course of disease development under the influence of etiology (pathogenesis), and the changes in function, metabolism and morphological structure of the body during the course of disease (lesion, pathological changes), clarify its essence, thereby providing a necessary theoretical basis for understanding and grasping the laws of disease occurrence and development, and for the prevention and treatment of diseases.

pathology is not only a basic discipline of medicine, but also a highly practical and characteristic discipline, which is called diagnostic pathology or surgical pathology. According to the differences in research objects, it can also be divided into human pathology and experimental pathology. Pathological diagnosis is often for the purpose of diagnosis, taking the patient or organs, tissues, cells or body fluids obtained from the patient's body as the object, including autopsy, surgical pathology and cytology. The main task of pathology is to study and clarify: ① etiology, that is, the causes of disease occurrence include internal causes, external causes and their interrelationships; ② pathogenesis (pathogenesis), that is, the specific links, mechanisms and processes that cause and develop diseases under the influence of etiology; ③ pathological change or lesion, that is, during the occurrence and development of a disease, The functional metabolism and morphological structure changes of the body and the relationship between these changes and manifestations (symptoms and signs) - clinical pathological correlation; ④ The prognosis and outcome of the disease, etc. Pathology lays a scientific theoretical foundation for grasping the essence of diseases, as well as for their diagnosis, treatment and prevention. The main task of diagnostic pathology is to study the lesion characteristics of various human diseases, thereby making pathological and differential diagnoses of diseases and directly serving the prevention and treatment of diseases.