What is the primary function of the circulatory system?

The primary function of the circulatory system is to transport oxygen and nutrients to cells throughout the body. This system is essential for maintaining homeostasis and ensuring that tissues receive the necessary elements they need for energy production, growth, and repair. Blood, which circulates within this system, carries oxygen from the lungs to cells and transports nutrients absorbed from food via the digestive system. Additionally, it aids in the removal of waste products, such as carbon dioxide and metabolic byproducts, from the cells, which are then expelled from the body.

This fundamental role is vital for sustaining life, as every cell depends on a steady supply of oxygen and nutrients to function effectively. While the circulatory system does indirectly support other functions, such as regulating body temperature or playing a role in hormone distribution, its core purpose is centered around transporting essential substances to and from cells.