6.2 - A - The Circulatory System
The circulatory system is the organ system responsible for transporting substances around the body and for removing waste from tissue cells. Some of the substances that are transported include:
This topic discusses the circulatory system, its components and how they respond to and are controlled by the brain.
William Harvey is credited with discovering that blood circulates and flows through the body. In his experiments, he was able show that blood flows through vessels in one direction and that blood is not consumed, but rather is recycled.
His experiment is shown in the diagram to the lower right. The basic premise was as follows:
Using this observation, he was able to conclude that blood flows in one direction. If this were not true, then lifting either finger would cause the vein to refill. Although his findings were not initially well-received by the scientific community, he toured Europe disproving other theories and eventually his was accepted.