• The human circulatory system is a network of organs that come together to function as one. Containing the heart, it is the cornerstone of the human body. With its complex network of arteries, veins and capillaries, every cell in the human body is able to do its job without fail.
  
  

Parts

• The circulatory system is divided into three parts, according to The Franklin Institute: The pulmonary, which has to do with the lungs; the coronary which consists of the heart; and the the systemic, which contains the rest of the circulatory system. Although separate, they must work together for the system to function correctly.
  
  

The Heart

• The human heart has four chambers. A division called the septum divides the heart into two distinct halves. The right half brings the oxygen-depleted blood from the rest of the body before sending it to the lungs. The left half of the heart then pumps the blood in from the lungs and out through the aorta. The blood then travels the entire body to deliver nutrients and oxygen, according to The Franklin Institute.
  
  

Red Blood Cells

• It takes a single blood cell about 30 seconds to make a complete trip through the entire pulmonary and systemic circulatory systems, according to MSN Encarta.
  
  

Capillaries

• If all the arteries, veins, and capillaries were laid out in the same manner, they would reach more than 60,000 miles. That would circle the Earth two and one half times, according to MSN Encarta.
  
  

Circulation

• In 1628, English professor William Harvey, theorized that the human body circulates the same blood, and therefore did not continuously make new blood. He concluded that it would be impossible for the liver to maintain an output of seven tons that is circulated daily by the human body, according to MSN Encarta.
  
  

Heartbeats

• Your heart will beat about 30 million times in a year, while pumping approximately 4,000 gallons of blood a day, according to Dr. Standley.com.
  
  

Blood Volume

• According to the Dr. Standley.com, a 3-year-old child has 2 pts. of blood in her body. An average adult has approximately 10 pts.
  
  

Waste Removal

• During renal circulation, the blood passes through the kidneys where waste is removed. The blood also passes through the liver, where the sugars are removed to be stored for later use, according to The Franklin Institute.
  
  

Blood Volume

• A normal heartbeat will move about 60 to 90 ml of blood through the heart. If the heart stops beating, death typically occurs within four minutes, according to MSN Encarta.
  
  

Damage Repair

• When the body is injured, the circulatory system sends clotting cells to stop the bleeding and proteins to promote healing. White blood cells and antibodies are then dispatched to prevent infection, according to MSN Encarta