The brain manages how we think, feel, learn and move. It also controls other important things in the body, such as breathing and heart rate.
The spinal cord is a long bundle of nerves down the middle of the spine (backbone). It starts at the base of the brain and goes down to the small of the back. Messages between the brain and other parts of the body travel through the spinal cord. The spine is made of bones called vertebrae. They protect the spinal cord.
Illustration of the spinal cord and central nervous system
The brain and the spinal cord together are called the central nervous system (CNS).
The brain and spinal cord are also covered and protected by three layers of tissue (membranes). These are called the meninges. The three layers are:
- the dura mater
- the arachnoid
- the pia mater (see diagram below).
The area between two of these layers is called the subarachnoid space. This space contains a liquid called cerebrospinal fluid (CSF).
CSF also fills spaces inside the brain called ventricles. CSF makes a protective cushion for the brain. It also takes nutrients to the brain and removes waste products.
Nerve cells (neurons)
The brain and spinal cord are made up of billions of nerve cells called neurons. They form a network to communicate with each other. They use this to send chemical messages between the brain and other parts of the body.
Nerve cells are held in place and supported by glial cells. There are different types of glial cells including astrocytes, oligodendrocytes and ependymal cells.
The main parts of the brain are the cerebrum, cerebellum, brain stem, cranial nerves and pituitary gland.
Illustration of a side view of the brain
This is the largest part of the brain and is made up of two halves, called hemispheres. It controls thinking, memory, behaviour and personality. The right half of the cerebrum controls the left side of the body. The left half of the cerebrum controls the right side of the body.
Each half of the cerebrum is divided into four areas, called lobes:
The frontal lobe
This is responsible for thinking, planning, problem solving and behaviour. Certain areas of the frontal lobe control movement in the arms and legs and how we produce speech.
The parietal lobe
This lobe helps us form words. It also helps us interpret touch and other sensations, and makes us aware of our body position.
The temporal lobe
The temporal lobe manages memory, feelings and understanding. It processes what we hear and smell. It also helps us with organising information, learning and speech.
The occipital lobe
The occipital lobe processes information about what we see, for example colour, shape and distance.
Illustration of a side view of the cerebrum
This is the area below the cerebrum, at the back of the brain (See diagram above: Side view of the brain). It controls balance and co-ordination.
The brain stem is at the bottom of the brain (See diagram above: Side view of the brain), connected to the spinal cord. It controls important body functions that keep us alive, such as:
- heart rate
- blood pressure
- body temperature
- eye movements
These are nerves that go from the brain and brain stem to the eyes, nose, ears, tongue, face and shoulders. They carry messages from these areas about sensations such as taste, smell, sight and hearing. They also carry messages to muscles that control eye and face movements, speech and swallowing.
The pituitary gland is a small, oval-shaped gland behind the nose at the base of the brain. It is below the optic nerves that lead to and from the eyes.
The pituitary gland makes hormones. Hormones are chemical messengers that help control growth and how the body works.
Hormones produced by the pituitary gland control other hormone-producing glands in the body.
The pineal gland is near the centre of the brain, between the two halves of the cerebrum. It makes a hormone called melatonin that helps control sleep patterns.