The cardiovascular system is responsible for transporting water, oxygen, carbon dioxide, and other nutrient and waste substances to and from cells. The term circulatory system is often used interchangeably with cardiovascular system. In this section, the term cardiovascular system includes the broader functions of the circulatory system, lymphatic system and hepatic system.
The arteries are part of the circulatory system that is responsible for delivering oxygen and nutrients to cells of the body, and for removing carbon dioxide and other waste products. As part of this system, the arteries carry blood away from the heart, to the organs and cells of the body. This is accomplished with the heart acting as a pump, forcing blood to circulate through the body. When the heart expands, it creates a low or diastolic pressure that fills the heart with blood. When the heart contracts, it causes a high, or systolic arterial pressure. This high pressure pulses blood into the arteries.
There are two major arteries leaving the heart: the pulmonary artery and the aorta. The heart contraction pumps blood into the pulmonary artery where it is carried to the lungs to be oxygenated. The oxygenated blood returns to the heart where another contraction pumps this newly oxygenated blood out the aorta. The aorta branches into into the systemic arteries carrying the oxygenated blood to organs and cells of the body. On each heart contraction, separate chambers of the heart pump blood into both the pulmonary and systemic artery systems.