The human brain is the command center for the human nervous system. It receives signals from the body's sensory organs and outputs information to the muscles. The human brain has the same basic structure as other mammal brains but is larger in relation to body size than any other brains.
Facts about the human brain
The human brain is the largest brain of all vertebrates relative to body size.
It weighs about 3.3 lbs. (1.5 kilograms).
The average male has a brain volume of 1,274 cubic centimeters.
The average female brain has a volume of 1,131 cm3.
The brain makes up about 2 percent of a human's body weight.
The cerebrum makes up 85 percent of the brain's weight.
It contains about 86 billion nerve cells (neurons) — the "gray matter."
It contains billions of nerve fibers (axons and dendrites) — the "white matter."
These neurons are connected by trillions of connections, or synapses.