Britannica
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Which parts make up the circulatory system?
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human body
Vintage anatomy charts of the human body showing the skeletal and muscle systems.
The human circulatory system is a complex network responsible for transporting nutrients, respiratory gases, and metabolic products throughout the body. It is primarily composed of the following elements:1
- Fluids: The system circulates two primary fluids: blood, which transports oxygen and nutrients, and lymph, which is part of the lymphatic system.12
- The Heart: This organ acts as the pump that drives the movement of blood through the body’s intricate network of vessels.12
- Blood Vessels: These include arteries, veins, and a vast network of microscopic capillaries where the exchange of substances between blood and tissues occurs.134
The system functions through two interacting modes of circulation: the cardiovascular system, which consists of pulmonary circulation (between the heart and lungs) and systemic circulation (between the heart and the rest of the body), and the lymphatic system. Together, these components ensure the integration of various tissues and the maintenance of homeostasis.154