# Effects of Drugs on Nervous Coordination This section outlines how various substances, particularly narcotic drugs, interfere with the normal functioning of the nervous system, leading to altered perception, mood, and physiological states. It also defines and explains the concepts of drug addiction and tolerance. Drugs are chemicals that interfere with how send, receive, and process information, often by mimicking natural neurotransmitters. They can alter moods and behaviors by changing brain chemistry, affecting regions like the brain stem, limbic system, and cerebral cortex. - **Narcotics:** A group of substances that diminish the perception of pain by binding to painkilling sites in the brain. Prolonged use can inhibit the body's production of natural painkilling chemicals (*endorphins*). - **Drug Addiction:** A state of dependence on a drug, where an individual feels a compulsive need to use the substance and finds it difficult to quit on their own. - **Drug Tolerance:** A diminished response to a drug that occurs with repeated use, requiring larger doses to achieve the original effect. ## Types of Narcotic Drugs ### Heroin - **Effect:** Induces a feeling of *euphoria* and provides pain relief. - **Side Effects:** Nausea, vomiting, and depression of the and circulatory systems, which can be fatal. ### Cannabis (Marijuana, Hashish) - **Source:** Dried flowering tops, leaves, and stem of the *Cannabis sativa* plant. - **Effect:** Mild euphoria, alterations in vision and judgment. - **Intoxication Signs:** Hallucinations, anxiety, and depression. ### Nicotine - **Source:** An alkaloid derived from tobacco. - **Effect:** Stimulates postsynaptic receptors (similar to *acetylcholine*), leading to increased skeletal muscle activity, , and . It is highly addictive as it triggers dopamine release in the brain. ### Alcohol - **Effect:** Acts as a *depressant*, slowing down nervous communication. - **Short-term Effects:** Impaired vision, judgment, and alertness. - **Long-term Effects:** Chronic use can damage the nervous system, liver, and pancreas. - **Withdrawal Symptoms:** Anxiety, irritability, depression, headaches, and hallucinations when use is suddenly stopped. ### Inhalants - **Source:** Volatile organic chemicals like glue, hair spray (aerosols), and ether (anesthetics). - **Effect:** Rapid onset of euphoria followed by central nervous system depression. - **Risks:** Deep inhalation can cause hallucinations or even death. These substances can also damage the myelin sheath of neurons. ## Drug Tolerance and Addiction: Specific Examples This section explores how tolerance and addiction develop with common substances like caffeine and nicotine. | Substance | Tolerance Development | Addiction Characteristics | Harmful Effects | | :--- | :--- | :--- | :--- | | **Caffeine** | The body becomes accustomed to its effects, requiring higher doses for the same level of alertness. | Does not cause classic addiction like other drugs, but a form of dependence can develop. | Insomnia, rapid heart rate, anxiety, high blood pressure, fatigue, irritability tremors, digestive issues. | | **Nicotine** | The body requires increasing amounts to achieve the same effects initially felt with lower doses. | Highly addictive. It produces temporary pleasing effects (dopamine release), leading to a cycle of repeated use to maintain the feeling. | Cancer, emphysema, infertility, insomnia, cardiovascular diseases, nausea, dizziness, headache, mouth ulcers. | ## Effects on the Central Nervous System (CNS) - **General Mechanism:** Drugs interfere with neuron communication by mimicking natural neurotransmitters, thereby activating or inhibiting neural pathways. - **Depressants (e.g., Alcohol):** Slow down the functioning of the CNS. - **Stimulants (e.g., Nicotine, Caffeine):** Increase physiological activity, such as heart rate, respiratory rate, and concentration.

5.8 Effects Of Drugs On Nfrvous Coordination | Nervous System Of Man | Biology 12