Dr. Richard Restak
associate professor of neurology at georgetown university medical school
the brain is the master control center of the body. the brain constantly receives information from the senses about conditions both inside the body and outside it, the brain rapidly analyzes this information and then sends out messages that control body functions and actions. the brain also stores information from past experience, which makes learning and remembering possible. in addition, the brain is the source of thoughts, moods, and emotions.
the human brain is a grayish pink, jelly-like ball with many ridges and grooves on its surface. a newborn baby's brain weighs less than one pound (0.5 kilograms) at birth. by the time a person is six years old, the brain has reached its full weight of about three pounds (1.4 kilograms). most of the brain cells are present at birth, and so the increase in weight comes mainly from growth of the cells. during this six year period, a person learns and acquires new behavior patterns at the fastest rate in life.
a network of blood vessels supplies the brain with the vast quantities of oxygen and food that it requires. the human brain makes up only 2 per cent of the total body weight, but it uses about 20 per cent of the oxygen used by the entire body when at rest. the brain can go without oxygen for only three to five minutes before serious brain damage results.
the brain is located at the upper end of the spinal cord. this cable of nerve cells extends from the neck about two thirds the way down the backbone. the spinal cord carries messages between the brain and other parts of the body. in addition, 12 pairs of nerves connect the brain directly with certain parts of the body.
the brain works somewhat like both a computer and a chemical factory. brain cells produce electrical signals and send them from cell to cell along pathways called circuits. as in a computer, these electical circuits receive, process, store and retrieve information. unlike a computer however, the brain creates its electrical signals by chemical means. the proper functioning of the brain depends on many complicated chemical substances produced by brain cells.
scientists in various fields work together to study the structure, function, and chemical composition of the brain. this field of study, called neuroscience or neurobiology, is rapidly increasing our understanding of the brain...but much remains to be learned. scientists do not yet know how much of the brain's acitivity can be explained by the current laws of physics and chemistry.