Biology Revision for "O" level examinations

Alcohol Abuse Alcohol in alcoholic beverages acts as a depressant of the central nervous system used in small amounts. Users feel more relaxed from anxiety, and become more self confident 2 . Some of the symptoms of alcoholism are as follows: Craving—A strong need, or urge, to drink. Loss of control—not being able to stop drinking once drinking has begun. Physical dependence—Withdrawal symptoms, such as nausea, sweating, shakiness, and anxiety after stopping drinking. Tolerance—the need to drink greater amounts of alcohol to feel the same effect. Physiological effect of consuming alcohol - Alcohol is absorbed from all parts of the gastrointestinal tract largely by simple diffusion into the blood 4 . It can be absorbed through the stomach walls. - Can change mood and behavior, and make it harder to think clearly and move with coordination 4 .   - Drinking a lot over a long time or too much on a single occasion can damage the heart, causi

"Drug abuse is the use of illegal drugs, or the misuse of prescription or over-the-counter drugs for at least a year with negative consequences". 1 http://www.parentfurther.com/sites/default/files/images/Drugs.jpg?1300484605 Drug: is a chemical that alters the functioning of living tissues 2 . Drugs can be used medically to improve health of an individual. However, when drugs are used in excessive amounts for non medical purposes, this is called drug abuse 3 . Some prescription drugs may be abused, such as tranquilizers (e.g. valium=addictive), antibiotics (overuse for minor infections), steroids (e.g. hormones used as performance enhancers by athletes), or even caffeine. Reference  1. http://www.nlm.nih.gov/medlineplus/ency/article/001945.htm 2. Anne Tindale , Biology: A concise revision course for CXC. Stanley Thornes (Publishers) Ltd. 3. Caribbean Examination Council. Biology, Resource for teachers. Book 5