What are brain tumours?
Brain tumours are clusters (lumps) of abnormal cells that have formed in the brain.
These tumours don’t often spread to other parts of the body, though they can spread through the brain tissue.
If brain tumours grow, they can press on and affect your normal brain tissue which may cause problems.
About the brain
Your brain is the centre of thought, feeling, memory, speech, vision, hearing, movement, and much more.
Your spinal cord, along with special nerves in the head (cranial nerves), help carry messages between the brain and the rest of the body. These messages do things like:
- Tell your muscles how to move
- Transmit information gathered by your senses
- Help coordinate the functions of your organs
Both the brain and spinal cord are referred to as your central nervous system (CNS).
Your skull protects the brain, and your spinal cord is protected by the bones of your spinal column.
The brain and spinal cord are surrounded and cushioned by a special liquid, called cerebrospinal fluid (CSF), which is located in spaces within the brain called ventricles.
The ventricles and the spaces around the brain and spinal cord are filled with CSF.
Parts of the brain and spinal cord
The main areas of the brain include the cerebrum, cerebellum, and brain stem. Each of these has a special function.
The ‘cerebrum’ is the large, outer part of your brain.
It has 2 hemispheres (halves) and controls reasoning, thought, emotion, and language.
The cerebrum is also responsible for planned muscle movements, like throwing a ball, walking and chewing.
It also takes in and understands vision, hearing, smell, touch, and pain.
Symptoms of cerebral tumours
The symptoms caused by a tumour in a cerebral hemisphere depend on where the tumour is located.
Common symptoms can include:
- Trouble speaking
- A change of mood such as depression
- A change in personality
- Weakness or paralysis in part of the body
- Changes in vision, hearing, or other senses
The ‘basal ganglia’ are structures deep within the brain that help control your muscle movements.
Tumours or other problems in this part of the brain usually cause weakness. In rare cases, they can cause tremors or other involuntary movements.
The ‘cerebellum’ lies under the cerebrum at the back part of the brain, and it helps coordinate movement.
Tumours of the cerebellum can cause problems with:
- Coordination in walking
- Precise movements of hands, arms, feet, and legs
- Swallowing or synchronizing eye movements
- Speech rhythm
The ‘brain stem’ is the lower part of your brain that connects to your spinal cord.
It contains bundles of very long nerve fibres. These fibres carry signals controlling muscles and sensation or feeling between the cerebrum and the rest the body.
Special centres in the brain stem also help control breathing and the beating of the heart.
Also, most cranial nerves (cranial nerves carry signals directly between the brain and the face, eyes, tongue, mouth, and some other areas) start in the brain stem.
Tumours in this critical area of the brain can cause:
- Stiff muscles
- Problems with sensation, facial or eye movement
- Problems with hearing and swallowing
- Double vision – a common early symptom
- Problems with coordination in walking
The spinal cord has bundles of very long nerve fibres.
These fibres carry signals that control muscles, sensation or feeling, and bladder and bowel control.
- Nerves that reach your arms begin in the spinal cord at the neck (cervical spine)
- Nerves that branch off the spinal cord to the legs, bowel, and bladder arise in the back (thoracic and lumbar spine)
Most spinal cord tumours start in the neck (cervical spine) and can cause symptoms in the arms and legs, as well as affect bowel and bladder function.
Spinal cord tumours below the neck only affect the legs and bowel and bladder function.
Spinal cord tumours usually cause symptoms on both sides of the body (for example, weakness or numbness of both legs). This is different from most brain tumours, which often affect only one side of the body.
Spinal cord tumours can cause weakness, paralysis, or numbness.
The ‘cranial nerves’ extend directly out of the base of the brain (as opposed to coming out of the spinal cord).
Tumours starting in cranial nerves can cause:
- Vision problems
- Trouble swallowing
- Hearing loss in one or both ears
- Facial paralysis, numbness, or pain