The human brain acts like "a powerful computer" that controls how people move, think and react, according to the Science Kids website explains. To protect this vital organ, more than 20 bones join together to create a protective covering called the cranium. Inside the skull, the brain floats in a cushion of cerebrospinal fluid that wards off infection and acts as a barrier to physical impact.
Size and Weight
A human brain, one of the body's largest organs, weighs about 3 lb. Animals such as dolphins, whales and elephants have larger brains, but the human brain is more developed and "packed to capacity," the National Geographic website states.
Cerebrum
The cerebrum, including the groovy, wrinkled cerebral cortex, makes up almost 85 percent of the brain. Its frontal lobes control speech, emotion and movement, while the parietal lobes process touch, temperature and pain. Occipital lobes enable people to see, while temporal lobes aid in hearing and memory.
Cerebellum and Brain Stem
Without the cerebellum, the brain's second-largest section, humans would not be able to balance or use their muscles. The cerebellum sends information to the spinal cord and neighboring sections of the brain. At the base of the brain, the brain stem controls vital physical functions such as breathing, blood pressure, sleeping and heart rate.
Left and Right Sides
The two sides of the brain help control opposite sides of the body. For example, the brain's right side interacts with the body's left side, while the brain's left side works with the body's right side, Science Kids website notes. An injury to one side of the brain affects the opposite side of the body, according the University of Washington's Neuroscience for Kids website.
Nerve Cells
The brain's 100 billion nerve cells transmit information to the rest of the body, coordinating physical and mental functions. To put it in perspective, Bryn Mawr College's website notes that each human brain has more nerve cells than the Milky Way galaxy has stars. If you lined up all the neurons in the brain, they would stretch 600 miles.
