The Circulatory System

 The circulatory system is a transport system that moves a variety of substances around the animal body. Its cargo includes things like hormones that help regulate body functions, nutrients and oxygen needed by cells, wastes produced by cells, and antibodies and inflammatory cells needed to protect the body.

General terminology

The blood vascular system consists of a fluid connective tissue (blood) which is moved through a closed system of tubes (blood vessels) by a powerful pump (the heart).

The lymphatic vascular system is a one-way system that helps protect the body by returning excess tissue fluid to the blood vascular system and defending the body against invasion by microorganisms.

The blood is a fluid connective tissue that transports cells and other substances around the body.