Inside the brain - How it works

The brain is the control centre of all of the body's functions. It is part of the central nervous system. This is the most highly developed and important system of the body. It is the centre which controls the body's functions, such as movement, speech, memory, thought etc. The brain also helps us to identify feelings and emotions which make up our personalities. Because of this it needs good protection and oxygen. It is protected by the skull which surrounds the brain tissue which in turn is covered by a tough covering called the 'dura' around the brain and spinal cord. The brain floats slightly within the skull because it is surrounded by cerebrospinal fluid which flows through the ventricles (open spaces within the brain) and around the brain and spinal cord. Blood provides oxygen and food.

The brain has two halves called the left and right hemispheres. The left hemisphere controls functions on the right side of the body and the right hemisphere controls the left side.

In most individuals the left side controls verbal functions such as the comprehension and production of speech and language as well as the ability to read, write and calculate. The right hemisphere is usually more important for visual abilities such as drawing, musical rhythm, judging distance and the size of objects etc.

Each cerebral hemisphere is divided into four different lobes which specialise in particular functions. The brain stem contains centres which control breathing, blood pressure and heart rate.

Inside the brain – Effects of injury

Even though the brain is well protected it can be injured. Damage to the brain may occur immediately or may develop after injury due to swelling or bleeding.
The problems which a brain injured person may encounter can include any one or more of the following according to which area within the brain has been affected:

• Physical changes
• Cognitive (thinking) problems
• Communication difficulties
• Emotional changes

It is important to remember that all people with brain damage do not have all or even most of the following problems. Each person is individually assessed to find out what the problems are and to plan rehabilitation.

Frontal lobe …
Physical
Increased or decreased interest in sex

Cognitive
Personality and behaviour e.g. childish joking, silliness, self centered behaviour, inability to see how other are reacting, lack of initiative, inappropriate social behaviour

Emotional
Lack of anxiety or concern for the future impulsiveness, restlessness, irritability, impatience

Occipital lobe …
Physical
Visual
e.g.. recognising or interpreting things when seen clearly

Cognitive
Recognition of familiar thingsCerebellum …

Physical
Coordination affecting everyday actions

Temporal Lobe …
Cognitive
Remembering and learning new things

Communication
Spoken language e.g. speech may be unintelligible (however may understand written language)

Limbic system …
Cognitive
Memory and new learning
Emotional
Control of emotions eg. tears or laughter for no apparent reason Control of aggression

Brain stem …

• Physical consciousness
• muscle tone
• stiffness and muscle spasm
• sensation to the face, mouth and tongue
• decreasing coughing and swallowing ability

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