The Nervous System

Illustrated diagram of the brain with major regions.

Your brain

Central Nervous System (CNS): Your CNS consists of the brain and spinal cord.

Cerebral Cortex: Involved in your thinking, learning and speaking activities.

Cerebrospinal fluid: Protects your brain and spinal cord by acting as a shock absorber.

Cerebrum: The largest and uppermost portion of your brain. It consists of the right and left hemispheres, which control thoughts and conscious action.

Corpus Callosum: Connects the two hemispheres of your brain and allows both sides to communicate. For example, when your right hand holds an object, your left hand knows it.

Thalamus: Egg-shaped area that helps you process and recognize information about touch, pain, temperature and pressure on your skin.

Frontal Lobe: helps to recognize future consequences resulting from current actions, or to choose between good and bad actions.

Hypothalamus: responsible for metabolic processes.

Optic Chiasma: where the optic nerves cross.

Brain Stem: Connects your brain with your spinal cord and controls your breathing and heart rate.

Pons: relays sensory information from the body to the brain, possibly even dreams.

Medulla Oblongata: deals with automatic functions like breathing and blood pressure.

Spinal Cord: transmits neural inputs between the body and the brain

Cerebellum: integrates sensory, coordination and motor control.

Occipital Lobe: visual processing center of the brain.

Your spinal cord

Your spinal cord is about as think as a thumb and 17 inches long, your spinal cord is actually an extension of your brain. Through your spinal cord, your brain can keep in constant contact with your whole body.

Illustrated diagram of the spinal cord with major regions.

Spinal cord anatomy

Spinal Column: Also called your backbone, your spinal column is made up of 33 small bones called vertebrae that fit together and form a protective tunnel for your spinal cord.

Spinal Cord: Your spinal cord is really a large nerve that extends from your brain stem to just below your ribs. Its millions of nerve fibers carry signals to and from your brain to other parts of your body.

Discs: Between your vertebrae are discs made of a tough, crabmeat like substance. These discs act as shock absorbers for your back and also help protect your spinal cord.

Spinal Nerves: Thirty-one pairs of nerves coming off your spinal cord that transmit messages to and form your body.

Motor Nerves: Nerves that carry impulses from your brain and spinal cord to your muscles, glands and other organs.

Sensory nerves: Nerves located in the skin and other sensory organs. These nerves receive stimuli and send impulses to your spinal cord and brain.

Vertebrae: Small bones with spiny projections that compose the backbone or spinal column.

The brain after injury

After a brain injury, people can experience the following:

  • Memory problems
  • Thinking, reasoning and concentration difficulties
  • Impaired vision and hearing
  • Speech problems
  • Motor problems (such as difficulty walking or the loss of hand, arm or leg function)
  • Fine motor problems (such as difficulty moving fingers when holding a pencil)
  • Behavior problems (such as impulsiveness or depression)
  • Paralysis of body parts
  • Seizures

Source: Big Head,by Dr. Pete Rowan. New York: Knopf, 1998.

The spinal cord after injury

A spinal cord injury can cause permanent paralysis, which is an inability to move a part of your body because of nerve or muscle damage. People can lose some or all body function below the point of injury as described in the following forms of paralysis:

Quadriplegia: ("Quad" means four and "plegia" means paralysis): If your spinal cord is injured near your neck, messages from your brain won't be able to go past that point. Paralyzed from the neck down, quadriplegics lose some or all function of their arms or legs.

Paraplegia: ("Para" means two and "plegia" means paralysis): Injury that occurs farther down the spinal cord causes paralysis from that location and below. Paraplegics suffer permanent loss of leg movement and lower-body function.

Once your spinal cord is damaged, it can never be fixed. And once your brain is injured and your brain cells are damaged, they can't be fixed either.
It's not like breaking an arm or a leg. Those body parts can heal. But a serious brain injury will rarely heal, and a spinal cord injury will never completely heal. Brain and spinal cord injuries can only be prevented, not treated!