What is Brain Cancer?

The Brain

The brain is a soft, spongy mass of tissue. It is protected by:

• The bones of the skull

• Three thin layers of tissue (meninges)

• Watery fluid (cerebrospinal fluid) that flows through spaces between the meninges and through spaces (ventricles) within the brain

This picture shows the brain and nearby structures.

The brain directs the things we choose to do (like walking and talking) and the things our body does without thinking (like breathing). The brain is also in charge of our senses (sight, hearing, touch, taste, and smell), memory, emotions, and personality.

A network of nerves carries messages back and forth between the brain and the rest of the body. Some nerves go directly from the brain to the eyes, ears, and other parts of the head. Other nerves run through the spinal cord to connect the brain with the other parts of the body.

When most normal cells grow old or get damaged, they die, and new cells take their place. Sometimes, this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor.

Primary brain tumors can be benign or malignant:

• Benign brain tumors do not contain cancer cells:

• Usually, benign tumors can be removed, and they seldom grow back.

• Benign brain tumors usually have an obvious border or edge. Cells from benign tumors rarely invade tissues around them. They don't spread to other parts of the body. However, benign tumors can press on sensitive areas of the brain and cause serious health problems.

• Unlike benign tumors in most other parts of the body, benign brain tumors are sometimes life threatening.

• Benign brain tumors may become malignant.

• Malignant brain tumors (also called brain cancer) contain cancer cells:

• Malignant brain tumors are generally more serious and often are a threat to life.

• They are likely to grow rapidly and crowd or invade the nearby healthy brain tissue.

• Cancer cells may break away from malignant brain tumors and spread to other parts of the brain or to the spinal cord. They rarely spread to other parts of the body.

Within the brain and spinal cord, glial cells surround nerve cells and hold them in place.

The three major parts of the brain control different activities:

• Cerebrum: The cerebrum uses information from our senses to tell us what is going on around us and tells our body how to respond. It controls reading, thinking, learning, speech, and emotions.

The cerebrum is divided into the left and right cerebral hemispheres. The right hemisphere controls the muscles on the left side of the body. The left hemisphere controls the muscles on the right side of the body.

• Cerebellum: The cerebellum controls balance for walking and standing, and other complex actions.

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