The cardiovascular system of the human body consists of the heart, the blood vessels and the blood that pumps through them. The body contains over 60,000 miles of blood vessels, if they were laid out end to end, according to the Texas Heart Institute. Blood, the fluid of life, travels through these vessels providing nutrients and protection to the cells throughout the body.
Circulation
The most important function of the cardiovascular system is pumping and circulating the blood. Electrical impulses trigger the heart muscle to contract propelling the blood to flow out of the heart through the largest artery known as the aorta. The blood leaving the heart is full of oxygen and nutrients ready to be carried to the cells.
As the heart continually contracts, the blood flows from the aorta to the smaller arteries and eventually to capillaries, vessels that are as thin as a strand of hair. The capillary walls are thin which allows the oxygen and nutrients to escape from the blood and flow into the cells. The waste-products produced by cells, including carbon dioxide, flow into the blood to be carried back to the lungs for removal.
In addition to circulating oxygen, nutrients and waste products, the cardiovascular system also transports hormones for use by certain cells or organs.
Protection
Another major function of the cardiovascular system is to protect the body from foreign invaders and the loss of blood. Blood is made up of plasma which is the liquid portion, platelets, red blood cells which carry oxygen and white blood cells which provide immunity.
White blood cells, which live only a few days to a few weeks, according to the Franklin Institute, are produced in the bone marrow. There are five different kinds of white blood cells, which together work to find foreign invaders such as bacteria, viruses or fungi and attack them until they dissolve. Some white blood cells, known as lymphocytes, produce antibodies against the toxins which not only fight the infection but also are able to remember the invader the next time it enters the body.
Platelets are not really cells, but instead just circulating fragments of cells according to the College of Public Health. Platelets contain proteins that make them sticky both to each other and to breaks in the blood vessel, therefore clotting the blood to prevent further bleeding.
Regulation
The cardiovascular system also functions to regulate body temperature, pH and the water content of cells. The capillaries are responsible for helping the body dissipate excess heat, as described by the Franklin Institute. As the body's temperature rises, the blood in the capillaries releases the heat out into the tissues. This is why the skin may appear flushed during exercise or exertion.
The pH (how acidic or alkaline a fluid is) of the body is regulated by the blood, which maintains a very small range of 7.35 to 7.45 for optimal function.
Plasma, which makes up about 55 percent of blood, is approximately 92 percent water as reported by the Franklin Institute. Water provides transportation for the cells in the blood and regulates the amount of water in the cells. If the cells have too much water, it will flow into the blood. Conversely if the cells have too little water, it will flow from the blood into the cells.
