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Bringing the Power of Science to Bear on Drug Abuse and Addiction

2: The brain is the most complex organ in the body

The brain is the most complex organ in the body

The brain is made up of a complex network of billions of nerve cells called neurons, as well as other kinds of cells, all protected by the bones of the skull. The typical brain weighs only about 3 pounds, but it is the source of most qualities that make you who you are. Neurons in the brain and spinal cord are part of the nervous system and act as a body’s “Command Central.”

The brain is constantly active, even when we are asleep. As a matter of fact, asleep or awake, the brain requires 20 percent of the heart’s output of fresh blood and 20 percent of the blood’s oxygen and glucose to keep functioning properly. Glucose is a type of sugar that is our brain’s primary fuel.

The brain produces enough electrical energy to power a 40-watt light bulb for 24 hours. That’s a lot of energy for a human organ a little bigger than a softball.

This page was last updated January 2007