Disease:
Disease is an extremely complicated process. Many times, from health to disease is a process from quantitative change to qualitative change.
When the external pathogenic factors act on cells, reaching a certain intensity or lasting for a certain time, that is to say, the pathogenic factors accumulate to a certain amount, which will cause cell damage, and the damaged cells will be disordered in function, metabolism and morphological structure.
The abnormal life activity process caused by self-regulation disorder for some reason causes a series of changes in metabolism, function and structure, which are manifested as abnormal symptoms, signs and behaviors. Disease is an abnormal life activity process caused by the disorder of balance regulation in the body after the body is injured by the cause under certain conditions.
Diseases that deviate from the normal form and function of human body, like health, can be defined differently from different angles. The most commonly used definition is "deviating from the normal form and function of the human body".
Modern medicine has measured various biological parameters of human body (including intelligence), and their values generally obey the normal distribution law in statistics, that is, an average value and the range of 95% healthy individuals can be calculated.
It is customary to call this range "normal". Beyond this range, too high or too low is "abnormal", and the disease belongs to the abnormal range.
This definition is applicable in many cases, for example, typhoid fever can be manifested as the increase of body temperature and blood "typhoid hemagglutinin" (antibody) in a certain period of time.
However, the individual differences and biological variations of normal people are great, and sometimes this definition does not apply.
If the heart size of a normal person is within a certain range, many diseases will cause the heart to become larger, but for athletes, bradycardia (as slow as 40 times per minute) is not pathological; This deviation from the normal value belongs to individual differences.
Mentally, it is the genius, not the patient, whose IQ greatly exceeds that of his peers. Some people define the disease from the perspective of function or adaptability, and think that the performance of the disease is that the function is damaged and the ability to coordinate with the environment is destroyed, so as not to mistake the individual differences and biological variations of normal people for diseases.
Sickle cell anemia only occurs when there is hypoxia, which is characterized by adaptability defect. For many mental patients, it is especially necessary to examine their ability to coordinate with the environment.
However, poor adaptive function is not necessarily a disease. For example, a mental worker who lacks physical activity for a long time can't adapt to the physical activities that ordinary people can do. If he is slightly tired, he will have backache, which is not necessarily a disease. Therefore, it is suggested to add a "disease-free state" between health and disease.