Below are the essential characteristics of the human circulatory system:

Blood, heart, blood vessels, and lymph make up the human circulatory system.
Blood is circulated in the human circulatory system in two chains (double circulation): one for oxygenated blood and the other for deoxygenated blood.
There are four chambers in the human heart: two ventricles and two auricles.
A body-wide network of blood vessels makes up the human circulatory system. Atherosclerosis affects arteries, nerves, and capillaries.
Blood arteries’ primary role is to distribute oxygenated blood and nutrients across the body. It’s also in charge of gathering metabolic wastes for expulsion from the body.
The duration of the circulatory system is not physically shown in most diagrams. If a human’s lungs, muscles, and capillaries were spread out end to end, they would cover a complete distance of 1,00,000 kilometres (or roughly eight times the diameter of the Earth).

ICSE, Grade 6, Science