What organs provide blood circulation and what is their significance?

Several organs can provide blood supply. Let’s consider everything on the example of a person. Our blood is formed with the help of red bone marrow. It moves through the body through the blood vessels: arteries, veins and capillaries. The heart is responsible for pumping blood. Our circulatory system is closely connected with the respiratory system, as the blood is enriched with oxygen in the lungs, and with the excretory system, as the blood gets rid of unnecessary substances through filtration in the kidneys. Some animals do not have a heart, but have one or more nodules that serve the same function.