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24 September 2014
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Organs - Brain

System: Nervous

Location: Inside your skull

Physical description: Pale grey, the size of a small cauliflower and the texture of pate

Function: To control your body and house your mind

Body and mind

Information, in the form of nerve impulses, travels to and from your brain along your spinal cord. This allows your brain to monitor and regulate unconscious body processes, such as digestion and breathing and to coordinate most voluntary movements of your body. It is also the site of your consciousness, allowing you to think, learn and create.

Your brain is made of many parts, each of which has a specific function. It can be divided into four areas: the cerebrum, the diencephalon, the brain stem and the cerebellum.


The cerebrum is the largest part of your brain. It sits on top of the rest of your brain, rather like a mushroom cap covering its stalk. It has a heavily folded grey surface, the pattern of which is different from one person to the next. Some of the grooves in its surface mark out different functional regions.

The front section of your cerebrum, the frontal lobe, is involved in speech, thought, emotion, and skilled movements. Behind this is the parietal lobe which perceives and interprets sensations like touch, temperature and pain. Behind this, at the centre back of your cerebrum, is a region called the occipital lobe which detects and interprets visual images. Either side of the cerebrum are the temporal lobes which are involved in hearing and storing memory.

The cerebrum is split down the middle into two halves called hemispheres that communicate with each other.


Your cerebellum is the second largest part of your brain. It sits underneath the back of your cerebrum and is shown in brown in the diagram above. It is involved in coordinating your muscles to allow precise movements and control of balance and posture.


Your diencephalon sits beneath the middle of your cerebrum and on top of your brain stem. It contains two important structures called the thalamus and the hypothalamus. Your thalamus acts as a relay station for incoming sensory nerve impulses, sending them on to appropriate regions of your brain for processing. It is responsible for letting your brain know what's happening outside of your body.

Your hypothalamus plays a vital role in keeping conditions inside your body constant. It does this by regulating your body temperature, thirst and hunger, amongst other things. And by controlling the release of hormones from the nearby pituitary gland.

Brain stem

Your brain stem is responsible for regulating many life support mechanisms, such as your heart rate, blood pressure, digestion and breathing. It also regulates when you sleep and wake.

Brain protection

Your brain is arguably your most important organ, but it is made of soft delicate tissue that would be injured by even the slightest pressure. As a result, it is well protected:

  • Three tough membranes called meninges surround your brain
  • The space between your brain and the meninges is filled with a clear fluid, which cushions your brain, provides it with energy and protects it against infection
  • Your skull encases your brain in a bony shell, cerebrospinal fluid and meninges

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