| Noun | 1. | circulatory system - the organs and tissues involved in circulating blood and lymph through the bodybody, organic structure, physical structure - the entire structure of an organism (an animal, plant, or human being); "he felt as if his whole body were on fire" liver - large and complicated reddish-brown glandular organ located in the upper right portion of the abdominal cavity; secretes bile and functions in metabolism of protein and carbohydrate and fat; synthesizes substances involved in the clotting of the blood; synthesizes vitamin A; detoxifies poisonous substances and breaks down worn-out erythrocytes ticker, heart, pump - the hollow muscular organ located behind the sternum and between the lungs; its rhythmic contractions move the blood through the body; "he stood still, his heart thumping wildly" blood stream, bloodstream - the blood flowing through the circulatory system lymph - a thin coagulable fluid (similar to plasma but) containing white blood cells (lymphocytes) and chyle; is conveyed to the blood stream by lymphatic vessels blood vessel - a vessel in which blood circulates vein, vena, venous blood vessel - a blood vessel that carries blood from the capillaries toward the heart; "all veins except the pulmonary vein carry unaerated blood" venous blood system, venation - (zoology) the system of venous blood vessels in an animal vascular system - the vessels and tissue that carry or circulate fluids such as blood or lymph or sap through the body of an animal or plant fetal circulation, foetal circulation - the system of blood vessels and structures through which blood moves in a fetus |