The brain and brain tumours

The brain

The brain and the spinal cord make up the central nervous system (CNS).  The brain is the  ‘control centre’ that coordinates lots of important body functions. The spinal cord connects the brain with nerves in most parts of the body.

The brain is contained inside the skull, which protects it. The brain is also protected by three thin layers of tissue (membrane) called the meninges, which cover the brain and spinal cord. In between two of these layers is a fluid called cerebrospinal fluid (CSF) that circulates around the brain and spinal cord.

The main parts of the brain are:

• the cerebrum
• the cerebellum
• the brain stem.

Cerebrum

This is at the top of the head and is the largest part of the brain. It’s made up of two halves, (hemispheres) and controls thinking, learning, memory, problem solving, emotions, touch and helps us be aware of our body position. 

Cerebellum

This is near the middle of the back of the head and controls movement, balance and coordination.

Brain stem

This connects the brain to the spinal cord and is in the lower part of the brain just above the back of the neck. It controls breathing, body temperature, heart rate and blood pressure, eye movements and swallowing.

Pituitary gland

This is in the middle of the brain. It makes hormones that control things such as growth, periods in girls, and sperm production in guys.

Types of brain tumour

There are different types of brain tumours. They’re usually named after the type of cells they develop from. 

Brain tumours can  be either benign (non-cancerous) or malignant (cancerous), and this information is about both types.

Benign brain tumours don’t spread into surrounding tissue, and if they can be removed with an operation they may not cause any more problems. But sometimes it‘s difficult to remove a benign tumour because of where it is in the brain, and treatment with chemotherapy or radiotherapy might be needed.

Some benign tumours can cause long-lasting changes either because they increase the pressure inside the brain or they press on important areas of the brain.

Malignant brain tumours can spread from where they started into surrounding brain tissue, causing pressure and problems in these parts of the brain. Or, they can spread through the fluid that surrounds the brain (called the cerebrospinal fluid) into other parts of the brain or the spinal cord. The spinal cord is made up of nerves that run down the middle of your back (spine) and pass messages from the brain to the rest of the body.

Sometimes cancers that start in other parts of the body can spread to the brain – known as secondary brain tumours.  This information is about tumours that start in the brain, which are called primary brain tumours.

The types of brain tumours most likely to affect teenagers are gliomas, medulloblastomas and germ cell tumours.

Gliomas

These start in the supporting cells of the brain known as glial cells. There are different types of glioma, but the ones that affect younger people are usually astrocytomas and ependymomas.

Astrocytomas

These are the most common type of glioma and develop from a star-shaped cell called an astrocyte. Doctors group them by how quickly they grow (known as the grade of the tumour) and how the cells look under a microscope.

Ependymomas 

These are a rarer type of glioma, which develop from cells that line the fluid-filled spaces (ventricles) of the brain and from the spinal cord. These are some of the tumours that can spread to the spine through the fluid that surrounds the brain and spinal cord.

Medulloblastomas

These usually start in the cerebellum, at the back part of the brain. Occasionally they may spread through the fluid that surrounds the brain (cerebrospinal fluid), or very rarely to other parts of the body. They start from very early cells that haven’t properly developed yet, and are sometimes called primitive neuroectodermal tumours (PNET).

Germ cell tumours of the brain

This type of tumour is rare. They develop from very early cells that produce eggs or sperm, called germ cell tumours. Although they often affect the ovaries in girls or the testicles in boys, they can also start in other parts of the body. They may be non-cancerous (benign) or cancerous (malignant) and are called by different names depending on what the cells look like under a microscope.

Causes

We don’t know the causes of most brain tumours, but research is going into this all the time. 

Young people with certain rare conditions that run in families (known as genetic conditions), such as neurofibromatosis type 1 and neurofibromatosis type 2, have an increased chance of developing brain tumours. 

There’s a lot in the news about whether using mobiles, or living near base stations or power lines are linked to brain tumours. But so far there’s no evidence that any of these increase the chances of a brain tumour.  However, mobiles haven’t been around that long so we’re still finding out more about their possible effects on our health.

Remember, it isn’t anything that you’ve done that’s caused it.