The cardiovascular system, also known as the circulatory system, transports nutrients, oxygen and water to all the cells in the body. The cardiovascular system consists of the heart, the blood vessels and the blood. The heart works as the motor, the blood vessels are the highways and the blood is the vehicle which carries the vital nutrients.
Heart
An adult heart is about the size of two fists put together. Although many believe the heart is located in the left side of the chest it is actually located in the center of the chest between the lungs. The heart is made of muscle that contracts to pump over 2,000 gallons of blood throughout the body each day, according to the Cleveland Clinic.
The heart is divided into four chambers. The two upper chambers are known as the atria and the two lower chambers are the ventricles. The right atrium receives oxygen-poor blood from the body and pumps it through the tricuspid valve, a one-way valve, to the right ventricle where the blood flows into the pulmonary artery into the lungs to receive oxygen.
The left atrium receives oxygen-rich blood from the lungs and it pumps through the mitral valve into the left ventricle where it is pumped out to the body to provide oxygen and nutrients to the cells. The atria and ventricles must work together as the muscle contracts and relaxes propelling blood flow. The right atrium contains the sinus node, a natural pacemaker that produces an electrical impulse regulating the heart's contractions.
Blood Vessels
In order for blood to move throughout the body, it must travel through a complex series of blood vessels. If all the blood vessels were taken out of a child and laid end to end, they would measure over 60,000 miles long and an adult contains close to 100,000 miles of vessels, according to the Franklin Institute.
There are three types of blood vessels. Arteries carry blood away from the heart. Most arteries carry oxygen-rich blood to the body. The arteries branch into smaller and smaller vessels that branch into the capillaries. Capillaries are tiny, thin-walled blood vessels which allow the oxygen, water and nutrients to pass through the vessel wall and into the cells of the tissues. Waste products from the cells, including carbon dioxide, also pass through the capillary walls into the blood which then travels back to the heart through the veins.
The transport of blood from the heart to the lungs is a little different. The oxygen-poor blood travels from the heart through the pulmonary artery to the lungs and the oxygen-rich blood travels back to the heart in the pulmonary vein.
Blood
Blood, the fluid of life, is made up of 78 percent water, according to the Cleveland Clinic. Blood also contains a variety of different cells. White blood cells are part of the immune system and function to protect the body against foreign invaders such as bacteria, viruses and fungi. Red blood cells carry oxygen that is delivered to cells. Platelets are cells that stick together and function to help blood clot.
