I am a very important component of blood, platelets, because small, many people mistakenly called me “small platelets”. First of all, we have a very strong function, that is, no matter where the blood vessels are in danger, we are the little vanguard of the charge. Secondly, we have an imperfectly fixed “establishment” in the blood, generally speaking, the normal between 100-300×10^9/L, which is the normal value defined by human beings after many measurements in the laboratory. And my teammates are very mobile and powerful, they can “block the gun”, “march for thousands of miles”, “go back and forth”, we are all “ready to die”. We are all good soldiers who are “at home in death”. Our life expectancy is about 7 days, but we have a powerful mother, “megakaryocytes”, she is like the “queen ant”, high production, but by the “hematopoietic stem cells” and other micro-environmental control, always keep us in the normal range. However, under the control of microenvironment such as “hematopoietic stem cells”, which always keep us within the normal range, when encountering stress such as broken blood vessels, we will work together to fight together and gather hand in hand until the blood vessels are repaired, bleeding stops, and the mission of blood clotting is accomplished, which ensures that broken blood vessels will not bleed too much. Therefore, in the case of bleeding from a blood vessel, fever and exercise that tends to damage the blood vessel and bleed, the measured platelet count will be mildly elevated, usually below 450×10^9/L, and at most not exceeding 1000×10^9/L.