[Music] The brain is the command center for the entire body; it makes us who we are. It receives
information from our senses and controls our thoughts and movement.
To better explore this incredibly complex organ, scientists have divided it into parts
and regions. The largest part is the cerebrum, which is
divided into two sides, called hemispheres, just like the earth. The outer layer is known
as the cortex, which is Latin for “bark.” Like a tree's bark, the surface is only 1/8
inch thick, but it also contains millions of cells with fibers that send messages to other
brain areas. More than 2/3 of the surface of the cortex
hides in hundreds of little folds that make the wiggly, visible lines on the brain. Animals
that are less intelligent have a smoother brain surface.
The cortex is divided into FOUR regions: THE FRONTAL LOBE is for personality and emotions,
higher thinking skills, like problem solving; and controlling movement. It continues to
develop until you are in your mid 20s. THE TEMPORAL LOBE helps process your hearing
and other senses, and helps with language and reading.
THE PARIETAL LOBE is involved with your senses, attention, and language.
THE OCCIPITAL LOBE helps your eyes see, including recognition of shapes and colors.
The THALAMUS, in the center of the brain, relays sensory and motor information to the
cortex and helps with consciousness, sleep and alertness.
Twelve pairs of cranial nerves carry information from your senses to and from the brain and
body. Lower in the brain we find the cerebellum,
which plays a key role in motor control, coordination, and spatial navigation, so we can find our
way out of a maze, for example. Underneath is the brain stem, which connects
the brain to the spinal cord, a nerve pathway that runs all the way down your back sending
and receiving information from your senses. The brain stem includes the PONS, which helps
control our breathing, and the MEDULLA OBLONGATA, which regulates
our heart, and other body reflexes like vomiting, coughing, sneezing, and swallowing.
The limbic system, a region under the cortex, processes our emotions and drives. It contains
the brain’s reward circuit which releases the chemical dopamine, making us feel pleasure.
The anticipation of pleasure motivates us to repeat important human behaviors like eating,
having fun with friends or falling in love. But it also encourages us to repeat risky
behaviors, like taking drugs. Drugs signal the brain to release unusually
strong amounts of dopamine. This flood of dopamine causes the “high” that drug users seek,
and makes it difficult to enjoy more normal, simple pleasures. Repeated activation of this
reward pathway can lead to addiction. The limbic system includes the AMYGDALA , which
processes emotions, and The HIPPOCAMPUS in the temporal lobe---which
is like a “memory indexer” that sends memories to certain parts of the brain for
storage, and retrieves them when you need them. The brain controls many actions through rapid nerve impulses, but there are some body functions
that the brain modulates over many hours or days, by secreting hormones via special glands,
like The HYPOTHALAMUS, which wakes you up in the
morning, and gets the adrenaline flowing, like during a test or athletic event.
The PITUITARY GLAND (often called the “master gland”) which helps control growth, body
temperature, pregnancy and child birth and the tiny PINEAL GLAND which helps to control
sleep and circadian rhythms. These are just a few of the parts and functions
of the beautiful, amazing, and complex human brain. It is the center of our world and seat
of our intelligence. We must exercise it, protect it, and understand how important it
is to every thought and action in our daily lives.