Understanding the brain: an introduction
The brain controls and coordinates
everything we do: movements, feelings, thoughts, breathing and
The brain is made up of billions of nerve cells that
communicate through electrical and chemical activity. It
weighs around 1.3 kg and is cushioned with the skull by
cerebrospinal fluid which circulates around the brain through a
series of cavities called ventricles.
The brain makes up only two percent of the body's weight but
uses 20% of the oxygen supply and blood flow. Brain cells are quite
fragile and need protection from trauma, pressure, infection,
poisoning or lack of oxygen. They begin to die if they do not
receive oxygen after three to five minutes.
The brain is divided into a number of parts, which have specific
functions and are designed to work together.
Hemispheres & lobes of the
The largest part of the brain is divided into two halves, with
the left half controlling the right side of the body and the right
half controlling the left side of the body.
These hemispheres will be more dominant for certain activities.
For example, the left hemisphere is mainly involved with
speech, language, reading and writing, while the right hemisphere
is usually more focused on visual perception, and interpreting
nonverbal information. Each hemisphere is divided into four
Frontal lobes are involved in problem-solving,
planning, making judgments, abstract thinking and regulating how we
act upon our emotions and impulses. Marked changes in a person's
personality and social skills can occur from damage to this
Temporal lobes are involved in receiving and
processing what we hear, visually recognizing objects, memory and
learning. The temporal lobes are also involved in personality,
emotions and sexual behaviour.
Parietal lobes are involved in monitoring
sensation and body position, understanding time, recognizing
objects, reading and judging the position of objects in the
Occipital lobes receive and interpret
information from our senses including colour, size, shape and
The cerebellum is located at the back and below the main
hemispheres of the brain. It controls balance and the muscle
coordination needed for large body movements. It lets a person know
how fast, how hard, how far and in what direction his or her body
parts are moving.
The brain stem
The brain stem connects the brain to the spinal cord and
regulates basic activities such as wakefulness, breathing,
swallowing, eye movement, body temperature and heart
This brief introduction to the brain reveals not only why the
brain is so vulnerable to injury, but also why the effects of a
brain injury can be so varied. Each part of the brain deals with
different aspects of what we think, feel and do so injury to
specific areas causes many different problems to arise.
The brain can be injured as a result of many things
including: a car accident, stroke, alcohol or drug abuse,
tumours, poisoning, infection, disease, near drowning, hemorrhage,
AIDS, and disorders such as Parkinson's disease, multiple
sclerosis, and Alzheimer's disease.
The good news is that the brain does have a limited
ability to heal itself and there are many rehabilitation strategies
to compensate for lost skills and abilities. See our complete range
of fact sheets for practical support.
References and further information