medical

This article conducts a popular science explanation on the question of "why don't our eyes fear the cold", and explains the reasons from two aspects: the structure of the eye and its physiological mechanisms. Firstly, the anterior surface of the eyeball has few temperature-sensitive nerve endings, and the cornea and sclera have few blood vessels, which results in poor heat dissipation. Secondly, blinking and eye movement can generate heat, and the eyelids, which are rich in blood vessels, can warm the eyeball, thus maintaining the surface temperature of the eyeball.

The article "Why Do People Always Blink Their Eyes?" introduces the definition, frequency, and physiological basis of blinking, explains the protective role of blinking, its neural reflex characteristics, and its function in emotional communication. It also describes the related manifestations of abnormal blinking and provides suggestions for correcting bad blinking habits.

This article focuses on the question of "Where does human appetite come from?" It points out that human appetite is regulated by the hunger center and satiety center in the ventromedial nucleus of the hypothalamus. At present, there are three hypotheses about the principle of appetite regulation: the fat regulation theory, the intestinal peptide regulation theory, and the sugar utilization rate regulation theory. At the same time, people can control their appetite rationally. The ancient saying "Eat when you're hungry and stop when you're full" and the health advocacy of eating until 70% to 80% fullness have important implications for healthy eating.

This article focuses on the question of "why can't humans control their own heartbeats", introducing the classification of human muscles, explaining the involuntary nature of the heart muscle, the pacemaker function of the sinoatrial node, and the regulatory mechanism of the autonomic nervous system on heartbeats, and explaining the reason why basic physiological activities such as heartbeats are usually not controlled by human consciousness.

This article focuses on the differences between the human brain and the animal brain, and introduces the main differences between the two from the perspectives of evolutionary development, the development of the neocortex, especially the prefrontal cortex, and the brain areas and functions related to human-specific language.

This article takes "Why do humans need to eat salt" as the theme, introduces the main component of salt, sodium chloride, and the background that inorganic salts such as sodium are essential for human body, elaborates on the distribution of sodium ions in the human body and the multiple physiological functions of sodium and chloride ions, and explains the various symptoms of long-term insufficient salt intake and the health risks of excessive salt intake. It also mentions that the World Health Organization recommends that adults consume no more than 5 grams of salt per day.

This article focuses on the question of why humans need to drink water, introducing that water is an important component of the human body, participating in various life activities of the human body, and that the human body cannot store water and excessive water loss can endanger life. It also explains the importance of drinking water in maintaining human life activities.

This article focuses on the topic of why the human body is asymmetric, introducing various asymmetric features of the human body, including its appearance, brain function, limbs, and internal organs. It explains the causes of asymmetry, including embryonic development and long-term lifestyle habits, and points out that obvious asymmetry may be a sign of facial nerve paralysis.

This article focuses on human-related medical knowledge, introducing the classification of modern medicine, the origin and development of medicine, and the significant contributions of medicine in preventing and controlling diseases and prolonging human lifespan

The article "What Medicine Has Brought to Humanity" demonstrates the significant contributions of medicine to humanity by citing data on population growth and increased human lifespan, the achievements of medical prevention and control of bacterial and viral infectious diseases, and various medical-related inventions that have won Nobel Prizes over the past century. It also mentions that in the 21st century, biologists and medical scientists have begun to focus on new research fields such as stem cell research.

This article focuses on the topic of "how medicine came into being", introducing early human understanding of diseases, the origin and development of ancient Chinese medicine, as well as the origin of Western ancient medicine and the important developmental processes and achievements of modern medicine at various stages.

This article takes "What is medicine?" as the theme and introduces medicine as a science that studies maintaining health and preventing and treating diseases. It is divided into two categories: modern medicine and traditional medicine. Modern medicine includes clinical medicine, basic medicine, preventive medicine, and specialized medicine, etc. The purpose of medicine is to solve people's health problems.