How does the Human Body Cardiovascular System Work?

In human body, the cardiovascular system, also known as the circulatory system, is an organ system of closed tubes (the capillaries, veins, and arteries) powered by a pump (the heart). It carries blood from the heart to all parts of the body and then returns the blood to the heart again.

The two-way functions of this closed-loop system include:
  • From heart 🠊 carrying oxygen and nutrients to the tissues; and;
  • To heart 🠊 transporting carbon dioxide and waste products from tissues for removal from the body.
The cardiovascular system consists of a four-chambered heart - right atrium, right ventricle, left atrium, and left ventricle – that rhythmically pumps blood and a series of vessels - arteries, veins, and capillaries - that carry blood from and to the body.

The cardiovascular system is intimately connected to the respiratory system, urinary system, and digestive system. The respiratory system is linked for the spontaneous supply of oxygen and elimination of carbon dioxide; the urinary system is closely associated for the filtration of blood and elimination of nitrogenous wastes; the digestive system is related for the pickup of nutrients.

How the Cardiovascular System Works?

pulmonary circuit

When we breathe in, oxygen travels through the components of the respiratory system. It then enters into the tiny air sacs, alveoli, of our lungs. From there oxygen diffuses into the bloodstream leaving the lungs. This oxygenated (oxygen-rich) blood then enters into the left side of the heart.

The heart then pumps it through a series of blood vessels to the different tissues of the whole body, including the neural component (neurons) of the nervous system. This oxygenated blood when reaches the capillaries in tissues, it delivers oxygen to the cells. And, of cource, the cells need the oxygen to produce energy.

When these cells produce energy, they release waste products (e.g., carbon dioxide and water). These waste products then diffuse into the bloodstream. The blood transports it back to the heart for elimination.

However, not all waste goes to the heart for removal, particularly nitrogenous wastes. The kidney (or the urinary system) cleans the blood from those wastes.

The deoxygenated (carbon dioxide rich) blood passes along the veins to enter the heart. It enters into the right side of the heart so that the heart can pump it back to the lungs.

The carbon dioxide from the deoxygenated blood diffuses into the alveoli to facilitate the process of exhalation through the respiratory system. The blood then absorbs fresh oxygen from the lungs and travels to the left side of the heart so that it can start the cycle again.

Image sources:
  • Pixabay.com
  • Pulmonary circuit by OpenStax College, CC-BY-3.0, via Wikimedia Commons