drug & beh txt 4-6

Quiz: Short Answer Questions

1. How does alcohol disrupt homeostasis, and what happens during alcohol withdrawal to counteract this disruption?

2. Describe the functions of glial cells in the nervous system.

3. What is an action potential, and how is it generated?

4. Explain the roles of the sympathetic and parasympathetic nervous systems in regulating bodily functions.

5. Identify the components of the basal ganglia and explain the effects of dopamine loss in this area.

6. Explain the role of the mesolimbic dopamine pathway in reward and drug dependence.

7. What are two ways in which drugs affect neurotransmission?

8. Describe the purpose and process of PET and fMRI brain imaging techniques.

9. What are the three types of drug names and give an example of each.

10. Explain what the therapeutic index is and why it is important for drug safety.

Quiz: Answer Key

1. Alcohol inhibits antidiuretic hormone (ADH), increasing urine excretion and disrupting fluid balance. During alcohol withdrawal, the body releases more vasopressin, leading to water retention to compensate for previous fluid loss.

2. Glial cells provide physical and nutritional support to neurons, remove dead neurons, regulate extracellular fluid, myelinate neurons, and form the blood-brain barrier.

3. An action potential is an electrical signal that allows neurons to communicate. It is generated by the opening of ion channels (Na+ and K+) that change the membrane's charge, leading to depolarization and repolarization.

4. The sympathetic nervous system prepares the body for "fight or flight" by increasing heart rate and dilating pupils, and uses norepinephrine as its neurotransmitter. The parasympathetic nervous system promotes "rest and digest" by slowing heart rate and constricting pupils, and uses acetylcholine.

5. The basal ganglia include the caudate nucleus, putamen, and globus pallidus, and are involved in muscle tone maintenance. Dopamine loss in this area leads to movement disorders like rigidity and difficulty initiating movement, as seen in Parkinson's disease.

6. The mesolimbic dopamine pathway, which runs from the ventral tegmental area (VTA) to the nucleus accumbens, is activated by both natural rewards and psychoactive drugs. This activation reinforces drug-seeking behavior, leading to dependence.

7. Drugs can affect neurotransmission by altering the availability of neurotransmitters in the synapse, or by directly interacting with neurotransmitter receptors as agonists or antagonists.

8. PET uses radioactively labeled chemicals to map the distribution of those chemicals in the brain, revealing information about glucose metabolism, blood flow, and receptor binding. fMRI measures metabolic activity in brain regions by detecting changes in blood flow, providing information about brain function.

9. The chemical name is the full description of the structure, like "7-(2-chloro-1-methylpropyl)-3,7-dihydro-1,3-dimethyl-1H-purine-2,6-dione," the generic name is the legal name, like "Caffeine," and the brand name is the trademarked name, like "NōDōz."

10. The therapeutic index (TI) is the ratio of the toxic dose (TD50) to the effective dose (ED50) of a drug. It is important for drug safety because a higher TI indicates a larger margin between the dose required for therapeutic effect and the dose that causes toxicity.

Essay Format Questions

1. Discuss the role of neurotransmitters in maintaining homeostasis and how psychoactive drugs can disrupt this balance.

2. Compare and contrast the mechanisms of action of cocaine and amphetamines, highlighting their effects on dopamine, norepinephrine, and serotonin systems.

3. Explain how the principles of pharmacokinetics (absorption, distribution, metabolism, and excretion) influence the effectiveness and duration of psychoactive drugs.

4. Describe the different types of tolerance that can develop with repeated drug use and how these contribute to drug dependence and withdrawal symptoms.

5. Analyze the ethical considerations surrounding animal testing in drug development, weighing the benefits of ensuring drug safety against the concerns for animal welfare.

Glossary of Key Terms

• Acetylcholine: A neurotransmitter involved in learning, memory, and muscle control; decreased levels are associated with Alzheimer's disease.

• Action Potential: An electrical signal that travels down a neuron's axon, triggering the release of neurotransmitters.

• Agonist: A drug or chemical that binds to a receptor and activates it, mimicking the effects of a neurotransmitter.

• Analgesic: A drug that relieves pain.

• Antagonist: A drug or chemical that binds to a receptor and blocks it, preventing a neurotransmitter from binding and exerting its effects.

• Astrocytes: A type of glial cell that supports neurons, provides glucose, and regulates neuronal activity.

• Autonomic Nervous System (ANS): Part of the peripheral nervous system that controls involuntary functions like heart rate, digestion, and blood pressure.

• Basal Ganglia: A group of brain structures involved in motor control and muscle tone maintenance; dysfunction can lead to movement disorders.

• Blood-Brain Barrier: A protective barrier that prevents many substances from entering the brain.

• Brand Name: The proprietary name of a drug, protected by trademark.

• Central Nervous System (CNS): The brain and spinal cord.

• Cerebral Cortex: The outer layer of the brain responsible for higher-level cognitive functions.

• Chemical Name: The precise chemical description of a drug.

• Cross-Tolerance: Tolerance to one drug conferring tolerance to other drugs in the same class.

• CYP450 Enzymes: A family of liver enzymes responsible for metabolizing many drugs.

• Dendrites: Branch-like extensions of a neuron that receive chemical signals from other neurons.

• Depolarization: A change in a neuron's membrane potential, making it less negative (more positive) and increasing the likelihood of an action potential.

• Dopamine: A neurotransmitter involved in reward, motivation, and motor control; implicated in addiction and Parkinson's disease.

• Dose-Response Curve: A graph showing the relationship between the dose of a drug and the magnitude of its effect.

• ED50: The effective dose of a drug for 50% of the population.

• Endorphins: Endogenous substances similar to morphine, involved in pain relief and reward.

• GABA (γ-aminobutyric acid): A major inhibitory neurotransmitter in the central nervous system.

• Generic Name: The official, non-proprietary name of a drug.

• Glia: Non-neuronal cells in the nervous system that provide support and protection for neurons.

• Glutamate: A major excitatory neurotransmitter in the central nervous system.

• Half-Life: The time it takes for the concentration of a drug in the blood to reduce by half.

• Hallucinogen: A drug that alters perception, thought, and mood.

• Homeostasis: The body's maintenance of stable internal conditions.

• Hyperpolarization: A change in a neuron's membrane potential, making it more negative and less likely to fire an action potential.

• Hypothalamus: A brain structure that regulates feeding, drinking, temperature, and sexual behavior.

• LD50: The lethal dose of a drug for 50% of the population.

• Limbic System: A group of brain structures involved in emotion, memory, and motivation.

• Lipid Solubility: The ability of a substance to dissolve in fats, which affects its ability to cross biological membranes like the blood-brain barrier.

• Metabolism: The process by which the body breaks down drugs and other substances.

• Mesolimbic Pathway: A dopamine pathway from the ventral tegmental area (VTA) to the nucleus accumbens, involved in reward and reinforcement.

• Neuron: A nerve cell responsible for communication and behavior.

• Neurotransmitter: A chemical messenger that transmits signals between neurons.

• Nigrostriatal Pathway: A dopamine pathway from the substantia nigra to the corpus striatum, important for motor control.

• Norepinephrine: A neurotransmitter involved in arousal, attentiveness, and food intake regulation.

• Pharmacodynamics: The study of how drugs affect the body.

• Pharmacokinetics: The study of how the body affects a drug (absorption, distribution, metabolism, and excretion).

• Placebo Effect: A psychological or physiological effect produced by an inactive substance or treatment that the recipient believes is a real drug.

• Potency: The amount of drug required to produce a particular effect.

• Psychoactive Drug: A drug that alters mood, thought processes, or behavior.

• Receptor: A protein on a cell surface that binds to a neurotransmitter or drug, initiating a cellular response.

• Repolarization: The return of a neuron's membrane potential to its resting state after depolarization.

• Reuptake: The process by which a neurotransmitter is transported back into the presynaptic neuron.

• Serotonin: A neurotransmitter involved in mood regulation, sleep, and appetite.

• Sodium-Potassium Pump: A protein that uses energy to restore Na+ and K+ ions to their original locations after an action potential.

• Somatic Nervous System: Part of the peripheral nervous system that controls voluntary muscle movements.

• Sympathetic Nervous System: The "fight or flight" branch of the autonomic nervous system.

• Therapeutic Index (TI): The ratio of the toxic dose (TD50) to the effective dose (ED50) of a drug.

• Tolerance: A decreased response to a drug after repeated use, requiring a higher dose to achieve the same effect.

• Withdrawal: A set of symptoms that occur when a drug is discontinued after prolonged use, resulting from physical dependence.