15 Year 3: Endocrine and Metabolic Pathology exam questions on Neurochemistry Test – Questions and Answers for medical students. Includes MCQs, answers, explana
This MCQ set contains 15 questions on Neurochemistry Test – Questions and Answers in the Year 3: Endocrine and Metabolic Pathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.
Correct answer: C – Endorphins
Endorphins are the body's natural opioids that create feelings of euphoria and pain relief. During intense exercise like running, the body releases endorphins, which bind to opioid receptors and produce the characteristic "runner's high" - a feeling of well-being and reduced pain perception. ---
Correct answer: C – In the nucleus
The nucleus contains the cell's DNA, which stores all genetic information. This DNA is transcribed into mRNA, which then travels to ribosomes for protein synthesis. The nucleus is the central control center for all cellular functions. ---
Correct answer: B – The role of sodium channels in depolarization
Tetrodotoxin specifically blocks voltage-gated sodium channels, preventing action potentials from occurring. This demonstrates that sodium influx through these channels is essential for depolarization and action potential generation. ---
Correct answer: C – Serotonin
Serotonin is strongly associated with mood regulation. Low serotonin levels are linked to depression, anxiety, and other mood disorders. SSRIs (Selective Serotonin Reuptake Inhibitors) are commonly prescribed antidepressants that increase serotonin availability. ---
Correct answer: C – Glutamate
Glutamate is the primary excitatory neurotransmitter in the brain. Excessive glutamate activity or insufficient GABA inhibition can lead to seizures, as the brain becomes hyperexcitable with uncontrolled neuronal firing. ---
Correct answer: C – Pleasure
Dopamine is central to the brain's reward system and pleasure pathways. It's released in response to rewarding experiences and motivates behavior toward pleasurable activities. This is why dopamine is often called the "feel-good" neurotransmitter. ---
Correct answer: E – Pleasure
Endorphins are the body's natural opioids that produce feelings of pleasure and well-being. They're released during exercise, stress, pain, and other activities, binding to opioid receptors to create euphoric feelings and reduce pain perception. ---
Correct answer: A – Acetylcholine
Alzheimer's disease involves significant loss of acetylcholine-producing neurons, particularly affecting memory and cognitive function. Cholinesterase inhibitors, which increase acetylcholine availability, are used as treatments for Alzheimer's. ---
Correct answer: A – Peptide neurotransmitter precursors and their enzymes are axonally transported in vesicles
Peptide neurotransmitters are synthesized in the cell body and transported down the axon in vesicles, while small-molecule neurotransmitters are typically synthesized locally at nerve terminals. This is a key distinguishing feature between these two types of neurotransmitters. ---
Correct answer: D – Norepinephrine
Most postganglionic sympathetic neurons release norepinephrine (noradrenaline) as their neurotransmitter. This activates adrenergic receptors on target organs, producing the "fight or flight" response characteristic of sympathetic activation. ---
Correct answer: D – During the absolute refractory period
During the absolute refractory period, sodium channels are inactivated and cannot be reopened regardless of stimulus strength. This ensures unidirectional propagation of action potentials and limits firing frequency. ---
Correct answer: B – Reduce neurotransmitter release at a synapse
Autoreceptors provide negative feedback control. When activated by the neurotransmitter they respond to, they reduce further neurotransmitter release, serving as a self-regulating mechanism to prevent excessive synaptic activity. ---
Correct answer: A – Exocytosis
Exocytosis is the process by which synaptic vesicles fuse with the presynaptic membrane and release their neurotransmitter contents into the synaptic cleft. This is triggered by calcium influx following action potential arrival. ---
Correct answer: D – Packaged in small synaptic vesicles
Small molecule neurotransmitters (like acetylcholine, dopamine, serotonin) are stored in small, clear synaptic vesicles, typically synthesized locally at nerve terminals, unlike peptide neurotransmitters which are made in the cell body. ---
Correct answer: A – Packaged in large synaptic vesicles
Small molecule neurotransmitters are packaged in small synaptic vesicles, not large ones. Large dense-core vesicles are typically used for peptide neurotransmitters and neuromodulators. ---