circulatory system

American  

noun

Anatomy, Zoology.

1. the system of organs and tissues, including the heart, blood, blood vessels, lymph, lymphatic vessels, and lymph glands, involved in circulating blood and lymph through the body.

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circulatory system British  

noun

1. anatomy zoology the system concerned with the transport of blood and lymph, consisting of the heart, blood vessels, lymph vessels, etc

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circulatory system Scientific  

/ sûr′kyə-lə-tôr′ē /

1. The system that circulates blood through the body, consisting of the heart and blood vessels. In all vertebrates and certain invertebrates, the circulatory system is completely contained within a network of vessels (known as a closed circulatory system). In arthropods and many other invertebrates, a substance analogous to blood (known as hemolymph) is pumped through vessels that open into the intercellular spaces (in what is known as an open circulatory system). In vertebrates, the lymphatic system is also considered part of the circulatory system.

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circulatory system Cultural  

1. The system in the body by which blood and lymph are circulated. The parts of the circulatory system include the heart, along with all the arteries, veins, and capillaries. The organs of the lymphatic system are also considered to be part of the circulatory system. Nutrients, oxygen, and other vital substances are carried throughout the body by the blood, which is pumped by rhythmic contractions of the heart. Blood is pumped from the heart to the arteries, which branch into smaller and smaller vessels as they move away from the heart. The blood passes oxygen and nutrients to the cells and picks up waste in the capillaries, then returns to the heart via a system of veins.

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Etymology

Origin of circulatory system

First recorded in 1860–65

Example Sentences

This slower pattern suggested that the fluid was part of the lymphatic system rather than the circulatory system.

From Science Daily • Apr. 9, 2026

He explains that snake venom enters the bloodstream within minutes, attacking nerves, cells, or the circulatory system depending on the species.

From BBC • Feb. 1, 2026

His frame is lit from within, head-to-toe, by argon trapped in electrified tubes shaped to resemble the human circulatory system, making his soul visible.

From Los Angeles Times • Oct. 16, 2025

From there, they can migrate to the circulatory system, and then spread and potentially affect every system in the body.

From Salon • Mar. 18, 2024

My circulatory system was getting messed up too, because even though it was a hundred-plus degrees in that boat my feet were cold.

From "Adrift" by Paul Griffin