CK12 Life Science

Table 20.3: (continued)

Disease Cause Symptoms

Parkinson’s Disease An abnormally low level of a

neurotransmitter affects the

part of the brain that con-

trols movement.

Rigid muscles, uncontrolled

shaking, slowed movements,

problems with speaking

Alzheimer’s Disease Abnormal changes in the

brain cause the gradual loss

of most normal brain func-

tions.

Memory loss, confusion,

mood swings, gradual loss

of control over mental and

physical abilities

Injuries to the Central Nervous System

Injuries to the central nervous system may damage tissues of the brain or spinal cord. If
an injury is mild, a person may have a full recovery. If an injury is severe, it may cause
permanent disability or even death. Brain and spinal cord injuries most commonly occur
because of car crashes or sports accidents. The best way to deal with such injuries is to try
to prevent them.

Brain Injuries

The mildest and most common type of brain injury is aconcussion. This is a bruise on
the surface of the brain. It may cause temporary problems such as headache, drowsiness,
and confusion. Most concussions in young people occur when they are playing sports, es-
pecially contact sports like football. A concussion normally heals on its own in a few days.
A single concussion is unlikely to cause permanent damage. However, repeated concussions
may lead to lasting problems. People that have had two or more concussions may have
life-long difficulties with memory, learning, speech, or balance. You can see an animation of
a how a concussion occurs by visitinghttp://pennhealth.com/health_info/animation-
player/concussion.html.

A person with a serious brain injury usually suffers permanent brain damage. As a result,
the person may have trouble talking or controlling body movements. Symptoms depend
on what part of the brain was injured. Serious brain injuries can also cause personality
changes and problems with mental abilities such as memory. Medicines, counseling, and
other treatments may help people with serious brain injuries recover from—or at least learn
to cope with—their disabilities.