I. Hematologic diseases and their scope Hematologic diseases refer to diseases that are primary (e.g., leukemia) or primarily involve (e.g., iron deficiency anemia) the blood and hematopoietic tissues and organs. The hematopoietic system includes the blood, bone marrow, spleen, lymph nodes, and lymphatic and mononuclear/phagocytic tissues scattered throughout the body. The blood consists of a cellular component, which includes red blood cells, various types of white blood cells and platelets, and a liquid component, which includes plasma. The liquid component, plasma, contains a variety of proteins with specific functions and certain other chemical components. Therefore, diseases that reflect the pathophysiology of the hematopoietic system and abnormalities in the plasma components are all diseases of the hematopoietic system and are customarily referred to as hematologic diseases. Clinically, hematologic diseases include various types of anemia, abnormalities of red blood cells and hemoglobin, various benign and malignant leukocyte diseases, various bleeding and clotting disorders, and diseases caused by abnormalities of various components in plasma. Second, the classification of blood system diseases blood system diseases are generally divided into the following categories. 1, red blood cell disease quantity changes such as various types of anemia, erythrocytosis, etc.; qualitative changes are often accompanied by quantitative changes, especially various types of anemia. There are also some quantitative changes that are less or non-existent, while qualitative changes are more significant, such as hereditary oval erythrocytosis, methemoglobinemia, and porphyria with defects in hemoglobin synthesis. 2, the decrease in the amount of leukocyte disease has congenital or drug, infection, immune and other factors that cause leukopenia or granulocyte deficiency. Leukocytosis is mostly caused by infection, inflammation, allergic reaction, cancer, etc. The qualitative changes are hematological malignancies such as leukemia, lymphoma, myeloma, etc. Neutrophil morphological abnormalities such as neutrophil lobar insufficiency and neutrophil functional defects with sui generis leukocyte syndrome are mainly manifested as granulocyte qualitative abnormalities. 3, bleeding and coagulation disorders are divided into three categories: platelet abnormalities, coagulation dysfunction and vessel wall abnormalities. Platelet quantity abnormalities are more common in thrombocytopenic purpura, in addition to thrombocytosis. The qualitative changes are platelet function abnormalities, such as platelet anemia. Coagulation disorders include coagulation factor deficiencies such as hemophilia, prothrombin deficiency, and various congenital or acquired deficiencies of other coagulation factors. Bleeding can also be caused by excess anticoagulant substances in the circulation, such as lesions with antiphospholipid antibodies or anti-factor VIII antibodies. Vascular wall abnormalities can be classified as allergic purpura caused by immune factors and hereditary hemorrhagic capillary dilation, etc. 4.Thrombotic diseases are divided into the following four categories according to the site, size and speed of thrombus formation, etc. Arterial thrombogenic diseases, such as myocardial ischemia and infarction, cerebral artery embolism, mesenteric artery embolism, and limb artery embolism. Venous thrombogenic diseases, such as deep venous thrombogenic diseases. Microcirculatory thrombogenic diseases, such as diffuse intravascular coagulation, thrombotic thrombocytopenic purpura, etc. Thromboembolic diseases, which commonly include embolism of lung, brain, spleen, kidney and other organs.