The brain and spinal cord

The brain and spinal cord make up the central nervous system (CNS). Together, the different parts of the CNS control how the mind and body work.

The brain – The brain receives and interprets information carried to it by nerves from the sensory organs that control taste, smell, touch, sight and hearing. It also sends messages through nerves to the muscles and organs. The brain is responsible for memory, personality and behaviour. The main parts of the brain are the cerebrum, the cerebellum and the brain stem.

Spinal cord – The spinal cord extends from the brain stem to the lower back. It is made up of nerve tissue that connects the brain to all parts of the body through a network of nerves called the peripheral nervous system. The spinal cord lies in the spinal canal, protected by a series of bones (vertebrae) called the spinal column.

Meninges – These are thin layers of protective tissue (membranes) that cover both the brain and spinal cord.

Cerebrospinal fluid (CSF) – Found inside the skull and spinal column, CSF surrounds the brain and spinal cord and protects them from injury.

Pituitary gland – This is found at the base of the brain and is about the size of a pea. The pituitary gland makes chemical messengers (hormones) and releases them into the blood. These hormones control many body functions, including growth, metabolism and development.

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The parts of the brain

The largest part of the brain is the cerebrum. It is divided into two halves called hemispheres. Each hemisphere is divided into four main areas – the frontal, parietal, occipital and temporal lobes.

• Left cerebral hemisphere – controls right side of the body and speech (for most people)
• Right cerebral hemisphere – controls left side of the body
• Corpus callosum – a thick band of nerve fibres that connects the two hemispheres and transfers information between them

The other main parts of the brain are the cerebellum and the brain stem. The cerebellum is found at the back of the head. The brain stem connects the brain to the spinal cord. Each part of the brain controls different bodily functions.

• Frontal lobe – controls thinking (cognition), planning and problem‑solving (executive function), emotions and personality, and body movement (motor function)
• Temporal lobe – controls memory, understanding and language
• Pituitary gland – makes hormones that control body functions and found deep inside the brain
• Parietal lobe – processes information from the senses (taste, smell, touch, sight, hearing)
• Occipital lobe – helps you understand what you see (vision)
• Cerebellum – coordinates movement, balance and posture
• Brain stem – controls functions that keep you alive, including breathing, swallowing, heart rate, blood pressure and sleep