The circulatory system also called the cardiovascular system or the vascular system. It is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis. Our body requires energy, nourishment, and oxygen. There is a need to transport various substances like digested food materials which are the sources of energy for the body from one part of the body to others. These functions are carried out by an extracellular fluid, which flows throughout the body. This flow is known as circulation, and this transport of substances is done by a system called the circulatory system.
The circulatory system is vital, and its constant movement of blood allows for gases and nutrients to be exchanged so the cells in our body can carry out their vital functions. Heart, along with the blood vessels, constitute the circulatory system. The circulatory system consists of three independent systems that work together: the heart (cardiovascular), lungs (pulmonary), and arteries, veins, coronary and portal vessels (systemic). The system is responsible for the flow of blood, nutrients, oxygen and other gases, and as well as hormones to and from cells. The circulatory system does a very important job in our body. It carries oxygen and essential nutrients to all cells around the body in arteries and carries the waste products and carbon dioxide in veins. The average human body contains over 60,000 miles of blood vessels.