Charles Holcomb, age 13, of New Bedford, Mass., for his question:
CAN YOU EXPLAIN THE WORKINGS OF THE BRAIN?
Master organ of the body is the brain. It receives messages from our eyes, ears, nose and skin. It also receives a steady stream of signals from other body organs that allow it to control our life processes.
The brain stores information from past experiences and makes it possible for us to learn, remember and think. The brain selects and combines messages from the senses with emotions and memories to form our various thoughts and reactions.
Scientists have not been able to tell us exactly how the brain works although they can count the billions of tiny neutrons and the mesh of fibers that do the brain's work. They don't know exactly what happens in the brain during learning that leaves a permanent trace recalled in memories.
Largest and most important part of the human brain is the cerebrum. It makes up about 85 percent of the brain's weight. Human beings highly developed cerebrum accounts for their intelligence.
Covering the cerebrum is a thin carpet of gray matter about an one eighth inch thick called the cerebral cortex. This layer folds in upon itself to form many grooves. The folding allows a large surface area of cerebral cortex to lie within the limited space of the skull.
The largest part of the cerebral cortex is concerned with complex mental processes such as memory, speech and thought. This is where the brain stores information.
The nerve cells scattered in brain's cerebral cortex are connected to nerve fibers called axons. The different regions in the cerebrum are called lobes although there is no real dividing line between the lobes.
The frontal lobes behind the forehead are thought to be the place where the most complex thinking takes place. It is here that both judgment and reasoning develop.
In the back part of the frontal lobes are the neurons that control voluntary movements of the whole body. There are certain spots, called motor areas, for movement of the feet, the face and the hands.
The brain has three main divisions: the forebrain, the midbrain and the hindbrain. Each division has many parts with special functions. The cerebrum is in the forebrain.
The human brain is a greatly expanded bulb at the upper end of the spinal cord. It is made up mainly of three different elements: (1) neutrons, or nerve cells, (2) glial cells, or supporting cells, and (3) blood vessels.
The nerve cells of the brain carry out the brain's functions while the glial cells form a supporting framework for the nerves. The brain is fed by a very complex maze of tiny blood vessels.