血液是人的生命之源,人体血管中的血液循环像人体内的“河流”川流不息,使各个系统、器官和组织生理机能得以正常“运行”。动脉负责将血液运输到器官和组织;毛细血管将血液中的营养物质和氧气供应给组织,组织中的代谢产物再通过毛细血管运走;最后,这些血液通过静脉系统运输回到心脏,心脏再将回流 Blood is the source of human life. Blood circulation in human blood vessels, like the “river” in the human body, continues to flow, enabling the normal functioning of the physiological functions of various systems, organs and tissues. Arteries are responsible for transporting blood to organs and tissues; capillaries supply nutrients and oxygen in the blood to tissues, and metabolites in tissues are transported away through capillaries; finally, the blood is transported back to the heart through the venous system, and then to the heart Will reflow