ADM Anatomy & Physiology Fundamentals 3 — Questions and Answers
Question 1: Cocaine produces its stimulant effects primarily by blocking which transporter?
- Vesicular monoamine transporter 2 (VMAT2)
- Dopamine transporter (DAT) (Correct answer)
- Serotonin transporter (SERT) only
- Norepinephrine transporter (NET) only
Correct answer: Dopamine transporter (DAT)
Cocaine blocks the dopamine transporter (DAT), preventing reuptake and causing dopamine accumulation in the synapse, producing its euphoric and stimulant effects.
Question 2: Which physiological process explains why repeated opioid use leads to tolerance?
- Downregulation and desensitization of mu opioid receptors (Correct answer)
- Upregulation of GABA receptors
- Increased production of endogenous opioids
- Decreased activity of the cytochrome P450 system
Correct answer: Downregulation and desensitization of mu opioid receptors
Chronic opioid exposure causes downregulation (reduced number) and desensitization (reduced responsiveness) of mu opioid receptors, requiring higher doses to achieve the same effect.
Question 3: The autonomic nervous system symptoms of opioid withdrawal (tachycardia, diaphoresis, piloerection) are primarily mediated by which brain structure?
- Cerebellum
- Hippocampus
- Locus coeruleus (Correct answer)
- Amygdala
Correct answer: Locus coeruleus
The locus coeruleus, the primary noradrenergic nucleus in the brain, becomes hyperactive during opioid withdrawal, producing the sympathetic autonomic symptoms.
Question 4: Nicotine exerts its addictive effects primarily by acting on which receptor type?
- Muscarinic acetylcholine receptors
- Nicotinic acetylcholine receptors (nAChRs) (Correct answer)
- AMPA glutamate receptors
- Alpha-2 adrenergic receptors
Correct answer: Nicotinic acetylcholine receptors (nAChRs)
Nicotine binds to nicotinic acetylcholine receptors (nAChRs), particularly α4β2 subtype in the VTA, stimulating dopamine release in the nucleus accumbens.
Question 5: Volume of distribution (Vd) is an important pharmacokinetic parameter. A highly lipophilic drug like THC would be expected to have a:
- Low Vd confined to plasma
- Moderate Vd equal to total body water
- Large Vd due to extensive tissue distribution (Correct answer)
- Vd equal to blood volume only
Correct answer: Large Vd due to extensive tissue distribution
Highly lipophilic substances like THC have a large volume of distribution because they readily partition into adipose and other tissues, explaining their prolonged detection in urine.
Question 6: Which portion of the adrenal gland releases cortisol in response to chronic stress, contributing to addiction vulnerability?
- Adrenal medulla
- Adrenal cortex (zona reticularis)
- Adrenal cortex (zona fasciculata) (Correct answer)
- Adrenal cortex (zona glomerulosa)
Correct answer: Adrenal cortex (zona fasciculata)
The zona fasciculata of the adrenal cortex produces glucocorticoids (cortisol), which are released in response to the HPA axis activation during stress and influence addiction vulnerability.
Question 7: The mesolimbic dopamine pathway originates in the ventral tegmental area (VTA) and projects primarily to which structure?
- Substantia nigra
- Nucleus accumbens and limbic structures (Correct answer)
- Cerebellum
- Spinal cord dorsal horn
Correct answer: Nucleus accumbens and limbic structures
The mesolimbic pathway projects from the VTA to the nucleus accumbens, amygdala, and hippocampus, forming the core of the brain's reward circuit.
ADM Anatomy & Physiology Fundamentals 3
Cocaine produces its stimulant effects primarily by blocking which transporter?