ADM Anatomy & Physiology Fundamentals 2 — Questions and Answers
Question 1: Which neurotransmitter system is most directly responsible for the euphoric effects of opioids in the ventral tegmental area (VTA)?
- Serotonergic system
- Dopaminergic system (Correct answer)
- GABAergic system
- Glutamatergic system
Correct answer: Dopaminergic system
Opioids disinhibit dopamine neurons in the VTA by suppressing GABAergic interneurons, leading to increased dopamine release in the nucleus accumbens and producing euphoria.
Question 2: The blood-brain barrier (BBB) is primarily formed by which cell type?
- Microglia
- Astrocytes
- Brain capillary endothelial cells with tight junctions (Correct answer)
- Oligodendrocytes
Correct answer: Brain capillary endothelial cells with tight junctions
Brain capillary endothelial cells connected by tight junctions form the primary structural basis of the BBB, which regulates substance entry into the CNS.
Question 3: Which hepatic enzyme system is primarily responsible for first-pass metabolism of most drugs of abuse?
- Monoamine oxidase (MAO)
- Cytochrome P450 (CYP) enzymes (Correct answer)
- Glucuronyl transferase
- Alcohol dehydrogenase
Correct answer: Cytochrome P450 (CYP) enzymes
The cytochrome P450 enzyme system, particularly CYP3A4, CYP2D6, and CYP2C19, handles first-pass metabolism of the majority of drugs including most substances of abuse.
Question 4: The nucleus accumbens, a key structure in addiction, is located within which brain region?
- Cerebellum
- Brainstem
- Ventral striatum (Correct answer)
- Thalamus
Correct answer: Ventral striatum
The nucleus accumbens is part of the ventral striatum and serves as a critical node in the mesolimbic reward circuit.
Question 5: Which receptor subtype mediates the analgesic and euphoric effects of heroin?
- Kappa (κ) opioid receptor
- Delta (δ) opioid receptor
- Mu (μ) opioid receptor (Correct answer)
- Nociceptin/OFQ receptor
Correct answer: Mu (μ) opioid receptor
The mu (μ) opioid receptor is the primary mediator of opioid analgesia, euphoria, and respiratory depression, making it central to opioid addiction.
Question 6: Alcohol primarily enhances which inhibitory neurotransmitter system in the brain?
- Glycinergic system
- GABA-A receptor system (Correct answer)
- Histaminergic system
- Adenosinergic system
Correct answer: GABA-A receptor system
Alcohol potentiates GABA-A receptor activity, increasing chloride influx and producing CNS depression, sedation, and anxiolysis.
Question 7: The prefrontal cortex (PFC) plays a critical role in addiction primarily through its regulation of which function?
- Respiratory drive
- Impulse control and executive decision-making (Correct answer)
- Cardiovascular homeostasis
- Pain signal transmission
Correct answer: Impulse control and executive decision-making
The prefrontal cortex governs executive functions including impulse control, decision-making, and inhibiting drug-seeking behavior, and its dysfunction underlies compulsive use in addiction.
ADM Anatomy & Physiology Fundamentals 2
Which neurotransmitter system is most directly responsible for the euphoric effects of opioids in the ventral tegmental area (VTA)?