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03. Circulatory System in Human Body
The circulatory system is a vital organ system that delivers essential substances to all cells for
basic functions to occur. Also commonly known as the cardiovascular system, is a network
composed of the heart as a centralized pump, bloods vessels that distribute blood throughout the
body, and the blood itself, for transportation of different substances.
The circulatory system is divided into two separate loops: The shorter pulmonary circuit that
exchanges blood between the heart and the lungs for oxygenation; and the longer systemic
circuit that distributes blood throughout all other systems and tissues of the body. Both of these
circuits begin and end in the heart.
OR
Circulatory system is the system which circulates everything throughout the body. Blood is
the fluid that circulates food and water to the different body parts. Blood flows through
blood vessels. Heart is the organ that pumps blood to the different parts.
Figure 3.1 (Circulatory system)