Anatomy & Physiology Fundamentals Flashcards

Benzodiazepine withdrawal can be life-threatening. Which physiological mechanism explains seizure risk during abrupt cessation?

Answer: NMDA glutamate receptor upregulation causing CNS excitability

Chronic benzodiazepine use causes compensatory upregulation of NMDA glutamate receptors; abrupt cessation removes GABA enhancement while glutamate excitability is heightened, causing seizures.

Methamphetamine causes neurotoxicity to dopaminergic terminals primarily through which mechanism?

Answer: Oxidative stress from excessive dopamine release and metabolism

Methamphetamine floods synapses with dopamine; excessive dopamine metabolism generates reactive oxygen species (ROS) causing oxidative stress and damage to dopaminergic terminals.

The half-life of a drug determines dosing intervals. Methadone has a half-life of approximately 24-36 hours, which means it reaches steady state after approximately:

Answer: 4-5 half-lives (4-7 days)

Steady state is reached after approximately 4-5 half-lives regardless of the drug; for methadone this means 4-7 days, which is why dose adjustments require careful monitoring.

The hypothalamic-pituitary-adrenal (HPA) axis plays a central role in stress and addiction. Which hormone is the primary driver of HPA axis activation?

Answer: Corticotropin-releasing hormone (CRH)

CRH released from the hypothalamus initiates the HPA stress cascade, stimulating pituitary ACTH secretion, which then drives adrenal cortisol production.

Which area of the brain is most associated with the formation of drug-related memories and conditioned cues that trigger craving?

Answer: Hippocampus and amygdala

The hippocampus encodes contextual memories associated with drug use while the amygdala processes emotional salience of drug cues, both driving cue-induced craving and relapse.

Alcohol is metabolized primarily in the liver. The primary enzyme responsible for the first step of ethanol metabolism is:

Answer: Alcohol dehydrogenase (ADH)

Alcohol dehydrogenase (ADH) in the liver cytosol is the primary enzyme converting ethanol to acetaldehyde, which is then further metabolized by aldehyde dehydrogenase.

The rewarding properties of all major drugs of abuse ultimately converge on increased dopamine signaling in which specific region?

Answer: Nucleus accumbens (NAc) shell

Despite diverse mechanisms, all major addictive substances ultimately increase dopamine in the nucleus accumbens shell, which is the final common pathway for drug reward.