http://www.ck12.org Chapter 1. Human Biology
FIGURE 1.98
These bacteria, shown at more than 1,000 times their actual size, are the
cause of bacterial meningitis. Despite their tiny size, they can cause very
serious illness.Reye’s Syndrome
A condition calledReye’s syndromecan occur in young people that take aspirin when they have a viral infection.
The syndrome causes swelling of the brain and may be fatal. Fortunately, Reye’s syndrome is very rare. The best
way to prevent it is by not taking aspirin when you have a viral infection. Products like cold medicines often contain
aspirin. So, read labels carefully when taking any medicines (Figure1.99).
FIGURE 1.99
Since 1988, the U.S. Food and Drug Ad-
ministration has required that all aspirin
and aspirin-containing products carry a
warning about Reye’s syndrome.Other Nervous System Diseases
Like other parts of the body, the nervous system may develop tumors. Atumoris a mass of cells that grows out of
control. A tumor in the brain may press on normal brain tissues. This can cause headaches, difficulty speaking, or
other problems, depending on where the tumor is located. Pressure from a tumor can even cause permanent brain
damage. In many cases, brain tumors can be removed with surgery. In other cases, tumors can’t be removed without
damaging the brain even more. In those cases, other types of treatments may be needed.
Cerebral palsyis a disease caused by injury to the developing brain. The injury occurs before, during, or shortly
after birth. Cerebral palsy is more common in babies that have a low weight at birth. But the cause of the brain
injury is not often known. The disease usually affects the parts of the brain that control body movements. Symptoms
range from weak muscles in mild cases to trouble walking and talking in more severe cases. There is no known cure
for cerebral palsy.
Epilepsyis a disease that causes seizures. A seizure is a period of lost consciousness that may include violent muscle
contractions. It is caused by abnormal electrical activity in the brain. The cause of epilepsy may be an infection, a
brain injury, or a tumor. The seizures of epilepsy can often be controlled with medicine. There is no known cure for
the disease, but children with epilepsy may outgrow it by adulthood.
A headache is a very common nervous system problem. Headaches may be a symptom of serious diseases, but they