THE HEART CARDIOVASCULAR SYSTEM
The Cardiovascular System
The components of the cardiovascular system are all the blood vessels within the body, the heart and the lungs.
The cardiovascular system is a highly complex part of the human body. The engine, pump or driving force behind all of this is the heart. Measuring about 300g, and about the size of a fist, the heart is an incredibly powerful pump that not only has to pump blood around the body at high pressure, but also has to pump blood to the lungs under low pressure. It is this “double pressure” system that makes the cardiovascular system so effective.
It is a four-chamber pump, with the right side receiving deoxygenated blood from the body at low pressure and pumping it to the lungs (the pulmonary circulation) and the left side receiving oxygenated blood from the lungs and pumping it at high pressure around the body (the systemic circulation).
The atria make up the upper portion of the heart whilst the ventricles make up the lower portion. Oxygen poor blood returning to the heart collects in the right atria before moving forward into the right ventricle. As this ventricle contracts, blood is forced up under low pressure into the lungs via the pulmonary artery where waste products of metabolism such as carbon dioxide are released. Fresh oxygen is taken up by haemoglobin in the blood and transported back down to the left atria via the pulmonary veins. This oxygen rich blood is then moved into the left ventricle ready for ejection into the aorta for transportation around the entire body.
The heart is therefore the pump responsible for maintaining adequate circulation of oxygenated blood around the vascular network of the body.