When various harmful factors, that is, the cause, act on the body, the body produces a series of anti-damage reactions to the damage caused by the cause, and the self-stabilizing regulation system tries to maintain the original balance. When the damage caused by the etiology is very serious, the function of the body's self-stabilizing regulation system is exhausted or disordered, and the balance of the body is destroyed, there will be pathological changes in the function, metabolism and morphological structure of various organs and tissues. These pathological changes can hinder the coordination between various organs and systems of the body and between the body and the external environment, thus causing various pathological symptoms, signs and behavioral abnormalities, especially weakening or even losing the ability to adapt to the environment and work. At this time, we said: the body is sick.
It can be seen that disease is a state, a state in which the internal environment is stable and the original balance is destroyed, and an abnormal state in the life activities of the body. Disease is also a process, a process in which harmful factors invade the body, the body fights against harmful factors and restores the original balance. The occurrence of disease is also a process, a gradual process from quantitative change to qualitative change.
People often think that no disease means health, and health means no disease, which puts health and disease in opposition. In fact, this is a wrong understanding. The World Health Organization (WHO) defines health as: health refers not only to the absence of disease or weakness, but also to a person's good state of physical, psychological and social adaptation.
The definition of health should be understood from two aspects: First, health not only refers to physical health, but also includes mental health and social adaptation. Many people think that as long as the body is healthy without disease, mental health is excluded from health. In fact, mental health problems will not only bring people pain, affect study and work, and cause social adaptation problems, but also affect physical health through the mediation of autonomic nerve, endocrine, immunity and behavior, leading to some serious physical and mental diseases, chronic diseases and cancer. Mind and body are a unified whole, which are interrelated and influence each other. Mental health will affect physical health, and physical health will affect mental health. Whether it is physical or mental health problems, it will affect the adaptation to society.
Secondly, there is no antagonistic relationship between health and disease, and there is no clear boundary between health and disease. It doesn't mean that you are sick without illness. There is a continuous belt between health and disease, from the end of the most serious disease to the peak of health, with a broad transition belt or middle belt in the middle. Everyone is at some point in this area, and most people are in a "normal" general health position in the middle. You may not be sick, but you may not be healthy. You may be in a sub-health state. Sub-health is a state close to disease, which may develop into a disease if it is not nursed back to health. So most of us can further improve our health and be healthier.
Many people often realize the importance of health after they get sick. In fact, we should pay attention to health preservation at ordinary times, strive to improve our health level and prevent diseases. So, what is the cause of the disease?
There are many causes of diseases, and different diseases often have different causes.
According to different properties, it can be divided into physical, chemical, biological and psychological sociality.
Physical pathogenic factors include: high temperature, low temperature, high pressure, low pressure, radiation of various rays, mechanical damage, etc. Chemical pathogenic factors include: all kinds of toxic chemicals, including all kinds of metals and nonmetals, such as lead, manganese, cadmium, thallium, arsenic, mercury, thallium and so on; Inorganic compounds and organic compounds, such as benzene, carbon monoxide, sulfide, nitrogen oxides, pesticides, etc. Biological pathogenic factors include: the invasion of various microbial pathogens and parasites such as bacteria, fungi and viruses, the degradation of the body's own tissues, metabolic disorders, immune disorders and so on. Psychosocial pathogenic factors include: all kinds of mental trauma, psychological pressure, negative emotional distress, as well as various social life events brought by social culture and psychological pressure brought by lifestyle changes.
In addition, the etiology can be divided into internal causes and external environmental causes according to different sources.
Internal pathogenic factors include: genetic defects and variation, endocrine and metabolic disorders, self-tissue degeneration, autoimmune function decline or disorder. The pathogenic factors of the external environment include: the damage and poison of various physical and chemical factors to the human body, the invasion of various microorganisms and germs, and the psychological stimulation brought by various social life events.
Although the occurrence of diseases is often the result of the interaction of internal and external factors, from the perspective of the history of human medical development, the pathogenic factors of external environment have always been the main factors threatening human health. Before the mid-20th century, the fatal diseases that did harm to human health were mainly infectious diseases caused by bacteria and viruses in the natural environment, such as plague, smallpox, cholera, measles and tuberculosis. Since the mid-20th century, with the application of antibiotics and vaccines, these infectious diseases have been well controlled. However, chronic diseases such as cancer, cardiovascular and cerebrovascular diseases and psychological diseases caused by human behavior have become the main threats to human health. In particular, if the deterioration of the ecological environment and environmental pollution cannot be effectively curbed, the survival of mankind will face great threats.