How Brain Cells Work

The healthy human brain contains many different types of cells. Neurons are nerve cells that process and send information throughout the brain, and from the brain to the muscles and organs of the body.

The ability of neurons to function and survive depends on three important processes:

• Communication. When a neuron receives signals from other neurons, it generates an electrical charge. This charge travels to the synapse, a tiny gap where chemicals called neurotransmitters are released and move across to another neuron.
• Metabolism. This process involves all chemical reactions that take place in a cell to support its survival and function. These reactions require oxygen and glucose, which are carried in blood flowing through the brain.
• Repair, remodeling, and regeneration. Neurons live a long time—more than 100 years in humans. As a result, they must constantly maintain and repair themselves. In addition, some brain regions continue to make new neurons.

Other types of brain cells, called glial cells, play critical roles in supporting neurons. In addition, the brain has an enormous network of blood vessels. Although the brain is only 2 percent of the body's weight, it receives 20 percent of the body's blood supply.