{ "chapter": "Coordination & Control", "count": 100, "answerIndex": "zero-based", "notice": "Original practice items including related concept variants; not official examination questions.", "questions": [ { "id": "depolarization", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which ion movement causes the rapid depolarization phase of a typical neuronal action potential?", "options": [ "Sodium enters", "Potassium enters", "Chloride leaves", "Calcium leaves the axon" ], "answer": 0, "explanation": "Voltage-gated sodium channels open, allowing sodium ions to enter down their electrochemical gradient." }, { "id": "myelin", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Myelin increases conduction speed mainly because action potentials are regenerated:", "options": [ "At every point on the membrane", "At nodes of Ranvier", "Only inside the cell body", "Inside synaptic vesicles" ], "answer": 1, "explanation": "Myelin insulates internodes, so local current travels rapidly and action potentials are regenerated at exposed nodes of Ranvier." }, { "id": "synaptic-calcium", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Voltage-gated calcium channels in a presynaptic terminal are blocked. Which event is reduced first?", "options": [ "Myelin formation", "Receptor synthesis in the nucleus", "Neurotransmitter exocytosis", "Sodium pumping in every neuron" ], "answer": 2, "explanation": "Calcium entry triggers synaptic vesicles to fuse with the presynaptic membrane and release neurotransmitter." }, { "id": "refractory-period", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "The refractory period helps an action potential move in one direction because the membrane immediately behind it:", "options": [ "Loses its phospholipids", "Has no ions", "Becomes permanently positive", "Cannot be re-excited normally" ], "answer": 3, "explanation": "Recently activated sodium channels are inactivated, so the region just behind the impulse cannot immediately fire again." }, { "id": "coordination-receptor-outcome", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "A sensory receptor detects an adequate stimulus. Which outcome follows most directly?", "options": [ "A generator potential develops in the receptor membrane", "Its interior remains negative relative to the outside", "An all-or-none action potential begins", "Impulses travel rapidly by saltatory conduction" ], "answer": 0, "explanation": "A generator potential develops in the receptor membrane. Stimulus energy opens or closes ion channels and changes membrane potential." }, { "id": "coordination-receptor-cause", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which change most directly explains this observation: a generator potential develops in the receptor membrane?", "options": [ "A neuron maintains ion gradients and greater resting permeability to potassium", "A sensory receptor detects an adequate stimulus", "Membrane depolarization reaches threshold at an axon hillock", "An axon is wrapped in insulating myelin" ], "answer": 1, "explanation": "A generator potential develops in the receptor membrane. Stimulus energy opens or closes ion channels and changes membrane potential." }, { "id": "coordination-receptor-mechanism", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After a sensory receptor detects an adequate stimulus, which explanation best links the change to its outcome?", "options": [ "Potassium leakage and the sodium-potassium pump create unequal charge distribution", "Sufficient voltage-gated sodium channels open through positive feedback", "Stimulus energy opens or closes ion channels and changes membrane potential", "Current spreads beneath myelin and action potentials regenerate mainly at nodes" ], "answer": 2, "explanation": "A generator potential develops in the receptor membrane. Stimulus energy opens or closes ion channels and changes membrane potential." }, { "id": "coordination-resting-potential-outcome", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After a neuron maintains ion gradients and greater resting permeability to potassium, which observation is most likely?", "options": [ "An all-or-none action potential begins", "Neurotransmitter can be released into the synaptic cleft", "Impulses travel rapidly by saltatory conduction", "Its interior remains negative relative to the outside" ], "answer": 3, "explanation": "Its interior remains negative relative to the outside. Potassium leakage and the sodium-potassium pump create unequal charge distribution." }, { "id": "coordination-resting-potential-cause", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "A learner records that its interior remains negative relative to the outside. Which preceding event best accounts for it?", "options": [ "A neuron maintains ion gradients and greater resting permeability to potassium", "An axon is wrapped in insulating myelin", "Membrane depolarization reaches threshold at an axon hillock", "An action potential reaches a presynaptic terminal" ], "answer": 0, "explanation": "Its interior remains negative relative to the outside. Potassium leakage and the sodium-potassium pump create unequal charge distribution." }, { "id": "coordination-resting-potential-mechanism", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After a neuron maintains ion gradients and greater resting permeability to potassium, which explanation best links the change to its outcome?", "options": [ "Sufficient voltage-gated sodium channels open through positive feedback", "Potassium leakage and the sodium-potassium pump create unequal charge distribution", "Depolarization opens calcium channels and calcium triggers vesicle fusion", "Current spreads beneath myelin and action potentials regenerate mainly at nodes" ], "answer": 1, "explanation": "Its interior remains negative relative to the outside. Potassium leakage and the sodium-potassium pump create unequal charge distribution." }, { "id": "coordination-resting-potential-integrated", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: a neuron maintains ion gradients and greater resting permeability to potassium?", "options": [ "Impulses travel rapidly by saltatory conduction — Current spreads beneath myelin and action potentials regenerate mainly at nodes", "An all-or-none action potential begins — Sufficient voltage-gated sodium channels open through positive feedback", "Its interior remains negative relative to the outside — Potassium leakage and the sodium-potassium pump create unequal charge distribution", "Neurotransmitter can be released into the synaptic cleft — Depolarization opens calcium channels and calcium triggers vesicle fusion" ], "answer": 2, "explanation": "Its interior remains negative relative to the outside. Potassium leakage and the sodium-potassium pump create unequal charge distribution." }, { "id": "coordination-threshold-outcome", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "A student models this change: Membrane depolarization reaches threshold at an axon hillock. What should the model predict first?", "options": [ "Impulses travel rapidly by saltatory conduction", "Neurotransmitter can be released into the synaptic cleft", "The limb moves before conscious analysis is complete", "An all-or-none action potential begins" ], "answer": 3, "explanation": "An all-or-none action potential begins. Sufficient voltage-gated sodium channels open through positive feedback." }, { "id": "coordination-threshold-cause", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "What is the most likely cause when an all-or-none action potential begins?", "options": [ "Membrane depolarization reaches threshold at an axon hillock", "An action potential reaches a presynaptic terminal", "A painful stimulus activates a spinal withdrawal reflex", "An axon is wrapped in insulating myelin" ], "answer": 0, "explanation": "An all-or-none action potential begins. Sufficient voltage-gated sodium channels open through positive feedback." }, { "id": "coordination-threshold-mechanism", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After membrane depolarization reaches threshold at an axon hillock, which explanation best links the change to its outcome?", "options": [ "Current spreads beneath myelin and action potentials regenerate mainly at nodes", "Sufficient voltage-gated sodium channels open through positive feedback", "Depolarization opens calcium channels and calcium triggers vesicle fusion", "Interneurons link sensory and motor pathways within the spinal cord" ], "answer": 1, "explanation": "An all-or-none action potential begins. Sufficient voltage-gated sodium channels open through positive feedback." }, { "id": "coordination-threshold-integrated", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: membrane depolarization reaches threshold at an axon hillock?", "options": [ "Impulses travel rapidly by saltatory conduction — Current spreads beneath myelin and action potentials regenerate mainly at nodes", "Neurotransmitter can be released into the synaptic cleft — Depolarization opens calcium channels and calcium triggers vesicle fusion", "An all-or-none action potential begins — Sufficient voltage-gated sodium channels open through positive feedback", "The limb moves before conscious analysis is complete — Interneurons link sensory and motor pathways within the spinal cord" ], "answer": 2, "explanation": "An all-or-none action potential begins. Sufficient voltage-gated sodium channels open through positive feedback." }, { "id": "coordination-myelin-outcome", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which immediate result is most consistent with this condition: An axon is wrapped in insulating myelin?", "options": [ "Neurotransmitter can be released into the synaptic cleft", "The limb moves before conscious analysis is complete", "Sodium enters and the membrane potential rapidly becomes less negative", "Impulses travel rapidly by saltatory conduction" ], "answer": 3, "explanation": "Impulses travel rapidly by saltatory conduction. Current spreads beneath myelin and action potentials regenerate mainly at nodes." }, { "id": "coordination-myelin-cause", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which condition would most specifically produce this result: impulses travel rapidly by saltatory conduction?", "options": [ "An axon is wrapped in insulating myelin", "An action potential reaches a presynaptic terminal", "A painful stimulus activates a spinal withdrawal reflex", "Voltage-gated sodium channels open in an axon membrane" ], "answer": 0, "explanation": "Impulses travel rapidly by saltatory conduction. Current spreads beneath myelin and action potentials regenerate mainly at nodes." }, { "id": "coordination-myelin-mechanism", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After an axon is wrapped in insulating myelin, which explanation best links the change to its outcome?", "options": [ "Depolarization opens calcium channels and calcium triggers vesicle fusion", "Current spreads beneath myelin and action potentials regenerate mainly at nodes", "Interneurons link sensory and motor pathways within the spinal cord", "Sodium moves inward down both its concentration and electrical gradients" ], "answer": 1, "explanation": "Impulses travel rapidly by saltatory conduction. Current spreads beneath myelin and action potentials regenerate mainly at nodes." }, { "id": "coordination-myelin-integrated", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: an axon is wrapped in insulating myelin?", "options": [ "Neurotransmitter can be released into the synaptic cleft — Depolarization opens calcium channels and calcium triggers vesicle fusion", "The limb moves before conscious analysis is complete — Interneurons link sensory and motor pathways within the spinal cord", "Impulses travel rapidly by saltatory conduction — Current spreads beneath myelin and action potentials regenerate mainly at nodes", "Sodium enters and the membrane potential rapidly becomes less negative — Sodium moves inward down both its concentration and electrical gradients" ], "answer": 2, "explanation": "Impulses travel rapidly by saltatory conduction. Current spreads beneath myelin and action potentials regenerate mainly at nodes." }, { "id": "coordination-synapse-outcome", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "An action potential reaches a presynaptic terminal. Which outcome follows most directly?", "options": [ "The action-potential membrane repolarizes", "The limb moves before conscious analysis is complete", "Sodium enters and the membrane potential rapidly becomes less negative", "Neurotransmitter can be released into the synaptic cleft" ], "answer": 3, "explanation": "Neurotransmitter can be released into the synaptic cleft. Depolarization opens calcium channels and calcium triggers vesicle fusion." }, { "id": "coordination-synapse-cause", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which change most directly explains this observation: neurotransmitter can be released into the synaptic cleft?", "options": [ "An action potential reaches a presynaptic terminal", "A painful stimulus activates a spinal withdrawal reflex", "Voltage-gated sodium channels open in an axon membrane", "Sodium channels inactivate and voltage-gated potassium channels open" ], "answer": 0, "explanation": "Neurotransmitter can be released into the synaptic cleft. Depolarization opens calcium channels and calcium triggers vesicle fusion." }, { "id": "coordination-synapse-mechanism", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After an action potential reaches a presynaptic terminal, which explanation best links the change to its outcome?", "options": [ "Interneurons link sensory and motor pathways within the spinal cord", "Depolarization opens calcium channels and calcium triggers vesicle fusion", "Sodium moves inward down both its concentration and electrical gradients", "Potassium efflux restores a negative internal potential" ], "answer": 1, "explanation": "Neurotransmitter can be released into the synaptic cleft. Depolarization opens calcium channels and calcium triggers vesicle fusion." }, { "id": "coordination-synapse-integrated", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: an action potential reaches a presynaptic terminal?", "options": [ "The limb moves before conscious analysis is complete — Interneurons link sensory and motor pathways within the spinal cord", "Sodium enters and the membrane potential rapidly becomes less negative — Sodium moves inward down both its concentration and electrical gradients", "Neurotransmitter can be released into the synaptic cleft — Depolarization opens calcium channels and calcium triggers vesicle fusion", "The action-potential membrane repolarizes — Potassium efflux restores a negative internal potential" ], "answer": 2, "explanation": "Neurotransmitter can be released into the synaptic cleft. Depolarization opens calcium channels and calcium triggers vesicle fusion." }, { "id": "coordination-reflex-outcome", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After a painful stimulus activates a spinal withdrawal reflex, which observation is most likely?", "options": [ "Sodium enters and the membrane potential rapidly becomes less negative", "The same region cannot fire again at once", "The action-potential membrane repolarizes", "The limb moves before conscious analysis is complete" ], "answer": 3, "explanation": "The limb moves before conscious analysis is complete. Interneurons link sensory and motor pathways within the spinal cord." }, { "id": "coordination-reflex-cause", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "A learner records that the limb moves before conscious analysis is complete. Which preceding event best accounts for it?", "options": [ "A painful stimulus activates a spinal withdrawal reflex", "Sodium channels inactivate and voltage-gated potassium channels open", "Voltage-gated sodium channels open in an axon membrane", "Sodium channels remain inactivated immediately after an action potential" ], "answer": 0, "explanation": "The limb moves before conscious analysis is complete. Interneurons link sensory and motor pathways within the spinal cord." }, { "id": "coordination-reflex-mechanism", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "After a painful stimulus activates a spinal withdrawal reflex, which explanation best links the change to its outcome?", "options": [ "Sodium moves inward down both its concentration and electrical gradients", "Interneurons link sensory and motor pathways within the spinal cord", "Channel recovery requires repolarization and creates the absolute refractory period", "Potassium efflux restores a negative internal potential" ], "answer": 1, "explanation": "The limb moves before conscious analysis is complete. Interneurons link sensory and motor pathways within the spinal cord." }, { "id": "coordination-reflex-integrated", "chapter": "Coordination & Control", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: a painful stimulus activates a spinal withdrawal reflex?", "options": [ "The action-potential membrane repolarizes — Potassium efflux restores a negative internal potential", "Sodium enters and the membrane potential rapidly becomes less negative — Sodium moves inward down both its concentration and electrical gradients", "The limb moves before conscious analysis is complete — Interneurons link sensory and motor pathways within the spinal cord", "The same region cannot fire again at once — Channel recovery requires repolarization and creates the absolute refractory period" ], "answer": 2, "explanation": "The limb moves before conscious analysis is complete. Interneurons link sensory and motor pathways within the spinal cord." }, { "id": "coordination-depolarization-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "A student models this change: Voltage-gated sodium channels open in an axon membrane. What should the model predict first?", "options": [ "The action-potential membrane repolarizes", "The same region cannot fire again at once", "Conduction speed increases", "Sodium enters and the membrane potential rapidly becomes less negative" ], "answer": 3, "explanation": "Sodium enters and the membrane potential rapidly becomes less negative. Sodium moves inward down both its concentration and electrical gradients." }, { "id": "coordination-depolarization-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "What is the most likely cause when sodium enters and the membrane potential rapidly becomes less negative?", "options": [ "Voltage-gated sodium channels open in an axon membrane", "Sodium channels remain inactivated immediately after an action potential", "Axon diameter increases while other properties remain equal", "Sodium channels inactivate and voltage-gated potassium channels open" ], "answer": 0, "explanation": "Sodium enters and the membrane potential rapidly becomes less negative. Sodium moves inward down both its concentration and electrical gradients." }, { "id": "coordination-depolarization-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After voltage-gated sodium channels open in an axon membrane, which explanation best links the change to its outcome?", "options": [ "Potassium efflux restores a negative internal potential", "Sodium moves inward down both its concentration and electrical gradients", "Channel recovery requires repolarization and creates the absolute refractory period", "The wider axon offers lower internal resistance to local current flow" ], "answer": 1, "explanation": "Sodium enters and the membrane potential rapidly becomes less negative. Sodium moves inward down both its concentration and electrical gradients." }, { "id": "coordination-repolarization-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: Sodium channels inactivate and voltage-gated potassium channels open?", "options": [ "The same region cannot fire again at once", "Conduction speed increases", "The action-potential membrane repolarizes", "The postsynaptic membrane depolarizes toward threshold" ], "answer": 2, "explanation": "The action-potential membrane repolarizes. Potassium efflux restores a negative internal potential." }, { "id": "coordination-repolarization-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: the action-potential membrane repolarizes?", "options": [ "An excitatory neurotransmitter opens ligand-gated cation channels", "Sodium channels remain inactivated immediately after an action potential", "Axon diameter increases while other properties remain equal", "Sodium channels inactivate and voltage-gated potassium channels open" ], "answer": 3, "explanation": "The action-potential membrane repolarizes. Potassium efflux restores a negative internal potential." }, { "id": "coordination-repolarization-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After sodium channels inactivate and voltage-gated potassium channels open, which explanation best links the change to its outcome?", "options": [ "Potassium efflux restores a negative internal potential", "Channel recovery requires repolarization and creates the absolute refractory period", "The wider axon offers lower internal resistance to local current flow", "Net positive-ion entry creates an excitatory postsynaptic potential" ], "answer": 0, "explanation": "The action-potential membrane repolarizes. Potassium efflux restores a negative internal potential." }, { "id": "coordination-repolarization-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: sodium channels inactivate and voltage-gated potassium channels open?", "options": [ "The same region cannot fire again at once — Channel recovery requires repolarization and creates the absolute refractory period", "The action-potential membrane repolarizes — Potassium efflux restores a negative internal potential", "Conduction speed increases — The wider axon offers lower internal resistance to local current flow", "The postsynaptic membrane depolarizes toward threshold — Net positive-ion entry creates an excitatory postsynaptic potential" ], "answer": 1, "explanation": "The action-potential membrane repolarizes. Potassium efflux restores a negative internal potential." }, { "id": "coordination-refractory-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Sodium channels remain inactivated immediately after an action potential. Which outcome follows most directly?", "options": [ "The postsynaptic membrane depolarizes toward threshold", "Conduction speed increases", "The same region cannot fire again at once", "Action-potential generation becomes less likely" ], "answer": 2, "explanation": "The same region cannot fire again at once. Channel recovery requires repolarization and creates the absolute refractory period." }, { "id": "coordination-refractory-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which change most directly explains this observation: the same region cannot fire again at once?", "options": [ "Axon diameter increases while other properties remain equal", "An inhibitory transmitter opens chloride channels", "An excitatory neurotransmitter opens ligand-gated cation channels", "Sodium channels remain inactivated immediately after an action potential" ], "answer": 3, "explanation": "The same region cannot fire again at once. Channel recovery requires repolarization and creates the absolute refractory period." }, { "id": "coordination-refractory-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After sodium channels remain inactivated immediately after an action potential, which explanation best links the change to its outcome?", "options": [ "Channel recovery requires repolarization and creates the absolute refractory period", "Net positive-ion entry creates an excitatory postsynaptic potential", "The wider axon offers lower internal resistance to local current flow", "Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane" ], "answer": 0, "explanation": "The same region cannot fire again at once. Channel recovery requires repolarization and creates the absolute refractory period." }, { "id": "coordination-refractory-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: sodium channels remain inactivated immediately after an action potential?", "options": [ "Conduction speed increases — The wider axon offers lower internal resistance to local current flow", "The same region cannot fire again at once — Channel recovery requires repolarization and creates the absolute refractory period", "Action-potential generation becomes less likely — Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "The postsynaptic membrane depolarizes toward threshold — Net positive-ion entry creates an excitatory postsynaptic potential" ], "answer": 1, "explanation": "The same region cannot fire again at once. Channel recovery requires repolarization and creates the absolute refractory period." }, { "id": "coordination-axon-diameter-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After axon diameter increases while other properties remain equal, which observation is most likely?", "options": [ "The postsynaptic membrane depolarizes toward threshold", "Action-potential generation becomes less likely", "Conduction speed increases", "Conscious perception, planning and voluntary action become possible" ], "answer": 2, "explanation": "Conduction speed increases. The wider axon offers lower internal resistance to local current flow." }, { "id": "coordination-axon-diameter-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "A learner records that conduction speed increases. Which preceding event best accounts for it?", "options": [ "An excitatory neurotransmitter opens ligand-gated cation channels", "An inhibitory transmitter opens chloride channels", "Neural activity is processed in the cerebral cortex", "Axon diameter increases while other properties remain equal" ], "answer": 3, "explanation": "Conduction speed increases. The wider axon offers lower internal resistance to local current flow." }, { "id": "coordination-axon-diameter-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After axon diameter increases while other properties remain equal, which explanation best links the change to its outcome?", "options": [ "The wider axon offers lower internal resistance to local current flow", "Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "Specialized cortical areas integrate sensory input with memory and motor commands", "Net positive-ion entry creates an excitatory postsynaptic potential" ], "answer": 0, "explanation": "Conduction speed increases. The wider axon offers lower internal resistance to local current flow." }, { "id": "coordination-axon-diameter-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: axon diameter increases while other properties remain equal?", "options": [ "The postsynaptic membrane depolarizes toward threshold — Net positive-ion entry creates an excitatory postsynaptic potential", "Conduction speed increases — The wider axon offers lower internal resistance to local current flow", "Action-potential generation becomes less likely — Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "Conscious perception, planning and voluntary action become possible — Specialized cortical areas integrate sensory input with memory and motor commands" ], "answer": 1, "explanation": "Conduction speed increases. The wider axon offers lower internal resistance to local current flow." }, { "id": "coordination-excitatory-synapse-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "A student models this change: An excitatory neurotransmitter opens ligand-gated cation channels. What should the model predict first?", "options": [ "Action-potential generation becomes less likely", "Conscious perception, planning and voluntary action become possible", "The postsynaptic membrane depolarizes toward threshold", "Posture, balance and movement precision improve" ], "answer": 2, "explanation": "The postsynaptic membrane depolarizes toward threshold. Net positive-ion entry creates an excitatory postsynaptic potential." }, { "id": "coordination-excitatory-synapse-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "What is the most likely cause when the postsynaptic membrane depolarizes toward threshold?", "options": [ "An inhibitory transmitter opens chloride channels", "Neural activity is processed in the cerebral cortex", "The cerebellum compares intended movement with sensory feedback", "An excitatory neurotransmitter opens ligand-gated cation channels" ], "answer": 3, "explanation": "The postsynaptic membrane depolarizes toward threshold. Net positive-ion entry creates an excitatory postsynaptic potential." }, { "id": "coordination-excitatory-synapse-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After an excitatory neurotransmitter opens ligand-gated cation channels, which explanation best links the change to its outcome?", "options": [ "Net positive-ion entry creates an excitatory postsynaptic potential", "Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "Specialized cortical areas integrate sensory input with memory and motor commands", "Error signals fine-tune motor output without initiating conscious commands" ], "answer": 0, "explanation": "The postsynaptic membrane depolarizes toward threshold. Net positive-ion entry creates an excitatory postsynaptic potential." }, { "id": "coordination-excitatory-synapse-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: an excitatory neurotransmitter opens ligand-gated cation channels?", "options": [ "Action-potential generation becomes less likely — Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "The postsynaptic membrane depolarizes toward threshold — Net positive-ion entry creates an excitatory postsynaptic potential", "Conscious perception, planning and voluntary action become possible — Specialized cortical areas integrate sensory input with memory and motor commands", "Posture, balance and movement precision improve — Error signals fine-tune motor output without initiating conscious commands" ], "answer": 1, "explanation": "The postsynaptic membrane depolarizes toward threshold. Net positive-ion entry creates an excitatory postsynaptic potential." }, { "id": "coordination-inhibitory-synapse-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: An inhibitory transmitter opens chloride channels?", "options": [ "Conscious perception, planning and voluntary action become possible", "Posture, balance and movement precision improve", "Action-potential generation becomes less likely", "Medullary respiratory centres increase ventilation" ], "answer": 2, "explanation": "Action-potential generation becomes less likely. Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane." }, { "id": "coordination-inhibitory-synapse-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: action-potential generation becomes less likely?", "options": [ "Blood carbon dioxide rises", "Neural activity is processed in the cerebral cortex", "The cerebellum compares intended movement with sensory feedback", "An inhibitory transmitter opens chloride channels" ], "answer": 3, "explanation": "Action-potential generation becomes less likely. Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane." }, { "id": "coordination-inhibitory-synapse-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After an inhibitory transmitter opens chloride channels, which explanation best links the change to its outcome?", "options": [ "Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "Specialized cortical areas integrate sensory input with memory and motor commands", "Error signals fine-tune motor output without initiating conscious commands", "Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing" ], "answer": 0, "explanation": "Action-potential generation becomes less likely. Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane." }, { "id": "coordination-inhibitory-synapse-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: an inhibitory transmitter opens chloride channels?", "options": [ "Conscious perception, planning and voluntary action become possible — Specialized cortical areas integrate sensory input with memory and motor commands", "Action-potential generation becomes less likely — Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane", "Posture, balance and movement precision improve — Error signals fine-tune motor output without initiating conscious commands", "Medullary respiratory centres increase ventilation — Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing" ], "answer": 1, "explanation": "Action-potential generation becomes less likely. Chloride entry stabilizes or hyperpolarizes the postsynaptic membrane." }, { "id": "coordination-cerebrum-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Neural activity is processed in the cerebral cortex. Which outcome follows most directly?", "options": [ "Medullary respiratory centres increase ventilation", "Posture, balance and movement precision improve", "Conscious perception, planning and voluntary action become possible", "The pupil constricts" ], "answer": 2, "explanation": "Conscious perception, planning and voluntary action become possible. Specialized cortical areas integrate sensory input with memory and motor commands." }, { "id": "coordination-cerebrum-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which change most directly explains this observation: conscious perception, planning and voluntary action become possible?", "options": [ "The cerebellum compares intended movement with sensory feedback", "Bright light strikes the retina", "Blood carbon dioxide rises", "Neural activity is processed in the cerebral cortex" ], "answer": 3, "explanation": "Conscious perception, planning and voluntary action become possible. Specialized cortical areas integrate sensory input with memory and motor commands." }, { "id": "coordination-cerebrum-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After neural activity is processed in the cerebral cortex, which explanation best links the change to its outcome?", "options": [ "Specialized cortical areas integrate sensory input with memory and motor commands", "Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing", "Error signals fine-tune motor output without initiating conscious commands", "A parasympathetic reflex contracts circular iris muscles and limits retinal illumination" ], "answer": 0, "explanation": "Conscious perception, planning and voluntary action become possible. Specialized cortical areas integrate sensory input with memory and motor commands." }, { "id": "coordination-cerebellum-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After the cerebellum compares intended movement with sensory feedback, which observation is most likely?", "options": [ "Medullary respiratory centres increase ventilation", "Posture, balance and movement precision improve", "The pupil constricts", "The lens becomes thicker and more strongly convex" ], "answer": 1, "explanation": "Posture, balance and movement precision improve. Error signals fine-tune motor output without initiating conscious commands." }, { "id": "coordination-cerebellum-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "A learner records that posture, balance and movement precision improve. Which preceding event best accounts for it?", "options": [ "Blood carbon dioxide rises", "Bright light strikes the retina", "The cerebellum compares intended movement with sensory feedback", "The eye focuses on a nearby object" ], "answer": 2, "explanation": "Posture, balance and movement precision improve. Error signals fine-tune motor output without initiating conscious commands." }, { "id": "coordination-cerebellum-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After the cerebellum compares intended movement with sensory feedback, which explanation best links the change to its outcome?", "options": [ "Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing", "A parasympathetic reflex contracts circular iris muscles and limits retinal illumination", "Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases", "Error signals fine-tune motor output without initiating conscious commands" ], "answer": 3, "explanation": "Posture, balance and movement precision improve. Error signals fine-tune motor output without initiating conscious commands." }, { "id": "coordination-cerebellum-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: the cerebellum compares intended movement with sensory feedback?", "options": [ "Posture, balance and movement precision improve — Error signals fine-tune motor output without initiating conscious commands", "Medullary respiratory centres increase ventilation — Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing", "The pupil constricts — A parasympathetic reflex contracts circular iris muscles and limits retinal illumination", "The lens becomes thicker and more strongly convex — Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases" ], "answer": 0, "explanation": "Posture, balance and movement precision improve. Error signals fine-tune motor output without initiating conscious commands." }, { "id": "coordination-medulla-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "A student models this change: Blood carbon dioxide rises. What should the model predict first?", "options": [ "The pupil constricts", "Medullary respiratory centres increase ventilation", "The lens becomes thicker and more strongly convex", "Heart rate rises and fuel becomes rapidly available" ], "answer": 1, "explanation": "Medullary respiratory centres increase ventilation. Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing." }, { "id": "coordination-medulla-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "What is the most likely cause when medullary respiratory centres increase ventilation?", "options": [ "Bright light strikes the retina", "The eye focuses on a nearby object", "Blood carbon dioxide rises", "Adrenaline enters the circulation during acute stress" ], "answer": 2, "explanation": "Medullary respiratory centres increase ventilation. Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing." }, { "id": "coordination-medulla-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After blood carbon dioxide rises, which explanation best links the change to its outcome?", "options": [ "The hormone activates adrenergic receptors in several target organs", "A parasympathetic reflex contracts circular iris muscles and limits retinal illumination", "Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases", "Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing" ], "answer": 3, "explanation": "Medullary respiratory centres increase ventilation. Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing." }, { "id": "coordination-medulla-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: blood carbon dioxide rises?", "options": [ "Medullary respiratory centres increase ventilation — Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing", "The pupil constricts — A parasympathetic reflex contracts circular iris muscles and limits retinal illumination", "The lens becomes thicker and more strongly convex — Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases", "Heart rate rises and fuel becomes rapidly available — The hormone activates adrenergic receptors in several target organs" ], "answer": 0, "explanation": "Medullary respiratory centres increase ventilation. Chemoreceptor input reflects hydrogen-ion changes and adjusts automatic breathing." }, { "id": "coordination-pupil-light-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: Bright light strikes the retina?", "options": [ "The lens becomes thicker and more strongly convex", "The pupil constricts", "Action potentials fail to propagate and paralysis may develop", "Heart rate rises and fuel becomes rapidly available" ], "answer": 1, "explanation": "The pupil constricts. A parasympathetic reflex contracts circular iris muscles and limits retinal illumination." }, { "id": "coordination-pupil-light-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: the pupil constricts?", "options": [ "Adrenaline enters the circulation during acute stress", "The eye focuses on a nearby object", "Bright light strikes the retina", "Tetrodotoxin blocks voltage-gated sodium channels" ], "answer": 2, "explanation": "The pupil constricts. A parasympathetic reflex contracts circular iris muscles and limits retinal illumination." }, { "id": "coordination-pupil-light-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After bright light strikes the retina, which explanation best links the change to its outcome?", "options": [ "Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases", "Regenerative sodium entry cannot produce depolarization in successive axon regions", "The hormone activates adrenergic receptors in several target organs", "A parasympathetic reflex contracts circular iris muscles and limits retinal illumination" ], "answer": 3, "explanation": "The pupil constricts. A parasympathetic reflex contracts circular iris muscles and limits retinal illumination." }, { "id": "coordination-pupil-light-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: bright light strikes the retina?", "options": [ "The pupil constricts — A parasympathetic reflex contracts circular iris muscles and limits retinal illumination", "Heart rate rises and fuel becomes rapidly available — The hormone activates adrenergic receptors in several target organs", "The lens becomes thicker and more strongly convex — Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases", "Action potentials fail to propagate and paralysis may develop — Regenerative sodium entry cannot produce depolarization in successive axon regions" ], "answer": 0, "explanation": "The pupil constricts. A parasympathetic reflex contracts circular iris muscles and limits retinal illumination." }, { "id": "coordination-accommodation-near-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "The eye focuses on a nearby object. Which outcome follows most directly?", "options": [ "Heart rate rises and fuel becomes rapidly available", "The lens becomes thicker and more strongly convex", "Action potentials fail to propagate and paralysis may develop", "Conduction slows or fails" ], "answer": 1, "explanation": "The lens becomes thicker and more strongly convex. Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases." }, { "id": "coordination-accommodation-near-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which change most directly explains this observation: the lens becomes thicker and more strongly convex?", "options": [ "Adrenaline enters the circulation during acute stress", "Tetrodotoxin blocks voltage-gated sodium channels", "The eye focuses on a nearby object", "Myelin is lost from sections of a central neuron" ], "answer": 2, "explanation": "The lens becomes thicker and more strongly convex. Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases." }, { "id": "coordination-accommodation-near-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After the eye focuses on a nearby object, which explanation best links the change to its outcome?", "options": [ "The hormone activates adrenergic receptors in several target organs", "Regenerative sodium entry cannot produce depolarization in successive axon regions", "Current leaks across exposed membrane before it can depolarize the next node", "Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases" ], "answer": 3, "explanation": "The lens becomes thicker and more strongly convex. Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases." }, { "id": "coordination-accommodation-near-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: the eye focuses on a nearby object?", "options": [ "The lens becomes thicker and more strongly convex — Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases", "Action potentials fail to propagate and paralysis may develop — Regenerative sodium entry cannot produce depolarization in successive axon regions", "Conduction slows or fails — Current leaks across exposed membrane before it can depolarize the next node", "Heart rate rises and fuel becomes rapidly available — The hormone activates adrenergic receptors in several target organs" ], "answer": 0, "explanation": "The lens becomes thicker and more strongly convex. Ciliary muscles contract, suspensory ligaments slacken and elastic lens curvature increases." }, { "id": "coordination-adrenaline-outcome", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After adrenaline enters the circulation during acute stress, which observation is most likely?", "options": [ "Action potentials fail to propagate and paralysis may develop", "Heart rate rises and fuel becomes rapidly available", "Conduction slows or fails", "Postsynaptic receptors remain stimulated longer than normal" ], "answer": 1, "explanation": "Heart rate rises and fuel becomes rapidly available. The hormone activates adrenergic receptors in several target organs." }, { "id": "coordination-adrenaline-cause", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "A learner records that heart rate rises and fuel becomes rapidly available. Which preceding event best accounts for it?", "options": [ "Tetrodotoxin blocks voltage-gated sodium channels", "Myelin is lost from sections of a central neuron", "Adrenaline enters the circulation during acute stress", "Acetylcholinesterase is inhibited at a cholinergic synapse" ], "answer": 2, "explanation": "Heart rate rises and fuel becomes rapidly available. The hormone activates adrenergic receptors in several target organs." }, { "id": "coordination-adrenaline-mechanism", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "After adrenaline enters the circulation during acute stress, which explanation best links the change to its outcome?", "options": [ "Regenerative sodium entry cannot produce depolarization in successive axon regions", "Current leaks across exposed membrane before it can depolarize the next node", "Acetylcholine accumulates because enzymatic clearance from the cleft is reduced", "The hormone activates adrenergic receptors in several target organs" ], "answer": 3, "explanation": "Heart rate rises and fuel becomes rapidly available. The hormone activates adrenergic receptors in several target organs." }, { "id": "coordination-adrenaline-integrated", "chapter": "Coordination & Control", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: adrenaline enters the circulation during acute stress?", "options": [ "Heart rate rises and fuel becomes rapidly available — The hormone activates adrenergic receptors in several target organs", "Action potentials fail to propagate and paralysis may develop — Regenerative sodium entry cannot produce depolarization in successive axon regions", "Conduction slows or fails — Current leaks across exposed membrane before it can depolarize the next node", "Postsynaptic receptors remain stimulated longer than normal — Acetylcholine accumulates because enzymatic clearance from the cleft is reduced" ], "answer": 0, "explanation": "Heart rate rises and fuel becomes rapidly available. The hormone activates adrenergic receptors in several target organs." }, { "id": "coordination-tetrodotoxin-outcome", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "A student models this change: Tetrodotoxin blocks voltage-gated sodium channels. What should the model predict first?", "options": [ "Conduction slows or fails", "Action potentials fail to propagate and paralysis may develop", "Postsynaptic receptors remain stimulated longer than normal", "Successive postsynaptic potentials may add to reach threshold" ], "answer": 1, "explanation": "Action potentials fail to propagate and paralysis may develop. Regenerative sodium entry cannot produce depolarization in successive axon regions." }, { "id": "coordination-tetrodotoxin-cause", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "What is the most likely cause when action potentials fail to propagate and paralysis may develop?", "options": [ "Myelin is lost from sections of a central neuron", "Acetylcholinesterase is inhibited at a cholinergic synapse", "Tetrodotoxin blocks voltage-gated sodium channels", "One presynaptic neuron fires repeatedly in rapid succession" ], "answer": 2, "explanation": "Action potentials fail to propagate and paralysis may develop. Regenerative sodium entry cannot produce depolarization in successive axon regions." }, { "id": "coordination-tetrodotoxin-mechanism", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After tetrodotoxin blocks voltage-gated sodium channels, which explanation best links the change to its outcome?", "options": [ "The membrane has not fully returned to baseline before the next signal arrives", "Current leaks across exposed membrane before it can depolarize the next node", "Acetylcholine accumulates because enzymatic clearance from the cleft is reduced", "Regenerative sodium entry cannot produce depolarization in successive axon regions" ], "answer": 3, "explanation": "Action potentials fail to propagate and paralysis may develop. Regenerative sodium entry cannot produce depolarization in successive axon regions." }, { "id": "coordination-demyelination-outcome", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which immediate result is most consistent with this condition: Myelin is lost from sections of a central neuron?", "options": [ "Conduction slows or fails", "Successive postsynaptic potentials may add to reach threshold", "No photoreceptor signal is generated at that location", "Postsynaptic receptors remain stimulated longer than normal" ], "answer": 0, "explanation": "Conduction slows or fails. Current leaks across exposed membrane before it can depolarize the next node." }, { "id": "coordination-demyelination-cause", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which condition would most specifically produce this result: conduction slows or fails?", "options": [ "Acetylcholinesterase is inhibited at a cholinergic synapse", "Myelin is lost from sections of a central neuron", "One presynaptic neuron fires repeatedly in rapid succession", "Light is focused on the optic disc" ], "answer": 1, "explanation": "Conduction slows or fails. Current leaks across exposed membrane before it can depolarize the next node." }, { "id": "coordination-demyelination-mechanism", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After myelin is lost from sections of a central neuron, which explanation best links the change to its outcome?", "options": [ "Acetylcholine accumulates because enzymatic clearance from the cleft is reduced", "The membrane has not fully returned to baseline before the next signal arrives", "Current leaks across exposed membrane before it can depolarize the next node", "Retinal axons exit there, leaving no rods or cones" ], "answer": 2, "explanation": "Conduction slows or fails. Current leaks across exposed membrane before it can depolarize the next node." }, { "id": "coordination-demyelination-integrated", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: myelin is lost from sections of a central neuron?", "options": [ "Postsynaptic receptors remain stimulated longer than normal — Acetylcholine accumulates because enzymatic clearance from the cleft is reduced", "Successive postsynaptic potentials may add to reach threshold — The membrane has not fully returned to baseline before the next signal arrives", "No photoreceptor signal is generated at that location — Retinal axons exit there, leaving no rods or cones", "Conduction slows or fails — Current leaks across exposed membrane before it can depolarize the next node" ], "answer": 3, "explanation": "Conduction slows or fails. Current leaks across exposed membrane before it can depolarize the next node." }, { "id": "coordination-acetylcholinesterase-outcome", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Acetylcholinesterase is inhibited at a cholinergic synapse. Which outcome follows most directly?", "options": [ "Postsynaptic receptors remain stimulated longer than normal", "Successive postsynaptic potentials may add to reach threshold", "No photoreceptor signal is generated at that location", "Blood glucose may remain high despite abundant insulin" ], "answer": 0, "explanation": "Postsynaptic receptors remain stimulated longer than normal. Acetylcholine accumulates because enzymatic clearance from the cleft is reduced." }, { "id": "coordination-acetylcholinesterase-cause", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which change most directly explains this observation: postsynaptic receptors remain stimulated longer than normal?", "options": [ "One presynaptic neuron fires repeatedly in rapid succession", "Acetylcholinesterase is inhibited at a cholinergic synapse", "Light is focused on the optic disc", "Target cells lose functional insulin receptors" ], "answer": 1, "explanation": "Postsynaptic receptors remain stimulated longer than normal. Acetylcholine accumulates because enzymatic clearance from the cleft is reduced." }, { "id": "coordination-acetylcholinesterase-mechanism", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After acetylcholinesterase is inhibited at a cholinergic synapse, which explanation best links the change to its outcome?", "options": [ "The membrane has not fully returned to baseline before the next signal arrives", "Retinal axons exit there, leaving no rods or cones", "Acetylcholine accumulates because enzymatic clearance from the cleft is reduced", "The hormone cannot trigger intracellular signalling for glucose uptake and storage" ], "answer": 2, "explanation": "Postsynaptic receptors remain stimulated longer than normal. Acetylcholine accumulates because enzymatic clearance from the cleft is reduced." }, { "id": "coordination-acetylcholinesterase-integrated", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: acetylcholinesterase is inhibited at a cholinergic synapse?", "options": [ "Successive postsynaptic potentials may add to reach threshold — The membrane has not fully returned to baseline before the next signal arrives", "No photoreceptor signal is generated at that location — Retinal axons exit there, leaving no rods or cones", "Blood glucose may remain high despite abundant insulin — The hormone cannot trigger intracellular signalling for glucose uptake and storage", "Postsynaptic receptors remain stimulated longer than normal — Acetylcholine accumulates because enzymatic clearance from the cleft is reduced" ], "answer": 3, "explanation": "Postsynaptic receptors remain stimulated longer than normal. Acetylcholine accumulates because enzymatic clearance from the cleft is reduced." }, { "id": "coordination-temporal-summation-outcome", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After one presynaptic neuron fires repeatedly in rapid succession, which observation is most likely?", "options": [ "Successive postsynaptic potentials may add to reach threshold", "No photoreceptor signal is generated at that location", "Blood glucose may remain high despite abundant insulin", "A generator potential develops in the receptor membrane" ], "answer": 0, "explanation": "Successive postsynaptic potentials may add to reach threshold. The membrane has not fully returned to baseline before the next signal arrives." }, { "id": "coordination-temporal-summation-cause", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "A learner records that successive postsynaptic potentials may add to reach threshold. Which preceding event best accounts for it?", "options": [ "Light is focused on the optic disc", "One presynaptic neuron fires repeatedly in rapid succession", "Target cells lose functional insulin receptors", "A sensory receptor detects an adequate stimulus" ], "answer": 1, "explanation": "Successive postsynaptic potentials may add to reach threshold. The membrane has not fully returned to baseline before the next signal arrives." }, { "id": "coordination-temporal-summation-mechanism", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After one presynaptic neuron fires repeatedly in rapid succession, which explanation best links the change to its outcome?", "options": [ "Retinal axons exit there, leaving no rods or cones", "The hormone cannot trigger intracellular signalling for glucose uptake and storage", "The membrane has not fully returned to baseline before the next signal arrives", "Stimulus energy opens or closes ion channels and changes membrane potential" ], "answer": 2, "explanation": "Successive postsynaptic potentials may add to reach threshold. The membrane has not fully returned to baseline before the next signal arrives." }, { "id": "coordination-temporal-summation-integrated", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: one presynaptic neuron fires repeatedly in rapid succession?", "options": [ "A generator potential develops in the receptor membrane — Stimulus energy opens or closes ion channels and changes membrane potential", "No photoreceptor signal is generated at that location — Retinal axons exit there, leaving no rods or cones", "Blood glucose may remain high despite abundant insulin — The hormone cannot trigger intracellular signalling for glucose uptake and storage", "Successive postsynaptic potentials may add to reach threshold — The membrane has not fully returned to baseline before the next signal arrives" ], "answer": 3, "explanation": "Successive postsynaptic potentials may add to reach threshold. The membrane has not fully returned to baseline before the next signal arrives." }, { "id": "coordination-blind-spot-outcome", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "A student models this change: Light is focused on the optic disc. What should the model predict first?", "options": [ "No photoreceptor signal is generated at that location", "A generator potential develops in the receptor membrane", "Blood glucose may remain high despite abundant insulin", "Its interior remains negative relative to the outside" ], "answer": 0, "explanation": "No photoreceptor signal is generated at that location. Retinal axons exit there, leaving no rods or cones." }, { "id": "coordination-blind-spot-cause", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "What is the most likely cause when no photoreceptor signal is generated at that location?", "options": [ "Target cells lose functional insulin receptors", "Light is focused on the optic disc", "A neuron maintains ion gradients and greater resting permeability to potassium", "A sensory receptor detects an adequate stimulus" ], "answer": 1, "explanation": "No photoreceptor signal is generated at that location. Retinal axons exit there, leaving no rods or cones." }, { "id": "coordination-blind-spot-mechanism", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After light is focused on the optic disc, which explanation best links the change to its outcome?", "options": [ "Stimulus energy opens or closes ion channels and changes membrane potential", "The hormone cannot trigger intracellular signalling for glucose uptake and storage", "Retinal axons exit there, leaving no rods or cones", "Potassium leakage and the sodium-potassium pump create unequal charge distribution" ], "answer": 2, "explanation": "No photoreceptor signal is generated at that location. Retinal axons exit there, leaving no rods or cones." }, { "id": "coordination-blind-spot-integrated", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: light is focused on the optic disc?", "options": [ "Blood glucose may remain high despite abundant insulin — The hormone cannot trigger intracellular signalling for glucose uptake and storage", "Its interior remains negative relative to the outside — Potassium leakage and the sodium-potassium pump create unequal charge distribution", "A generator potential develops in the receptor membrane — Stimulus energy opens or closes ion channels and changes membrane potential", "No photoreceptor signal is generated at that location — Retinal axons exit there, leaving no rods or cones" ], "answer": 3, "explanation": "No photoreceptor signal is generated at that location. Retinal axons exit there, leaving no rods or cones." }, { "id": "coordination-insulin-receptor-outcome", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which immediate result is most consistent with this condition: Target cells lose functional insulin receptors?", "options": [ "Blood glucose may remain high despite abundant insulin", "Its interior remains negative relative to the outside", "An all-or-none action potential begins", "A generator potential develops in the receptor membrane" ], "answer": 0, "explanation": "Blood glucose may remain high despite abundant insulin. The hormone cannot trigger intracellular signalling for glucose uptake and storage." }, { "id": "coordination-insulin-receptor-cause", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which condition would most specifically produce this result: blood glucose may remain high despite abundant insulin?", "options": [ "A sensory receptor detects an adequate stimulus", "Target cells lose functional insulin receptors", "A neuron maintains ion gradients and greater resting permeability to potassium", "Membrane depolarization reaches threshold at an axon hillock" ], "answer": 1, "explanation": "Blood glucose may remain high despite abundant insulin. The hormone cannot trigger intracellular signalling for glucose uptake and storage." }, { "id": "coordination-insulin-receptor-mechanism", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "After target cells lose functional insulin receptors, which explanation best links the change to its outcome?", "options": [ "Stimulus energy opens or closes ion channels and changes membrane potential", "Potassium leakage and the sodium-potassium pump create unequal charge distribution", "The hormone cannot trigger intracellular signalling for glucose uptake and storage", "Sufficient voltage-gated sodium channels open through positive feedback" ], "answer": 2, "explanation": "Blood glucose may remain high despite abundant insulin. The hormone cannot trigger intracellular signalling for glucose uptake and storage." }, { "id": "coordination-insulin-receptor-integrated", "chapter": "Coordination & Control", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: target cells lose functional insulin receptors?", "options": [ "A generator potential develops in the receptor membrane — Stimulus energy opens or closes ion channels and changes membrane potential", "Its interior remains negative relative to the outside — Potassium leakage and the sodium-potassium pump create unequal charge distribution", "An all-or-none action potential begins — Sufficient voltage-gated sodium channels open through positive feedback", "Blood glucose may remain high despite abundant insulin — The hormone cannot trigger intracellular signalling for glucose uptake and storage" ], "answer": 3, "explanation": "Blood glucose may remain high despite abundant insulin. The hormone cannot trigger intracellular signalling for glucose uptake and storage." }, { "chapter": "Coordination & Control", "id": "applied-reflex-order", "difficulty": "Foundation", "stem": "Which label belongs at X in the simplified withdrawal reflex pathway?", "options": [ "Sensory neuron", "Photoreceptor", "Endocrine gland", "Motor neuron" ], "answer": 0, "explanation": "The sensory neuron carries impulses from the receptor towards the spinal cord. A motor neuron carries the output towards the effector.", "visual": { "kind": "flow", "caption": "Withdrawal reflex; arrows show impulse direction", "nodes": [ "Skin receptor", "X", "Spinal cord relay", "Motor neuron", "Muscle" ] } }, { "chapter": "Coordination & Control", "id": "applied-conduction-speed", "difficulty": "Standard", "stem": "An impulse travels 0.8 m along an axon in 0.02 s. What is its average conduction speed?", "options": [ "0.016 m s⁻¹", "40 m s⁻¹", "4 m s⁻¹", "400 m s⁻¹" ], "answer": 1, "explanation": "Speed = distance ÷ time = 0.8 ÷ 0.02 = 40 m s⁻¹. The units are metres per second, not seconds per metre." }, { "chapter": "Coordination & Control", "id": "applied-synaptic-calcium", "difficulty": "Challenge", "stem": "An action potential reaches a presynaptic terminal, but its voltage-gated calcium channels are blocked. What should decline first?", "options": [ "Neurotransmitter receptor synthesis throughout the body", "Action potential amplitude in every sensory neuron", "Vesicle fusion and neurotransmitter release", "Myelin thickness along the postsynaptic neuron" ], "answer": 2, "explanation": "Calcium entry at the terminal triggers vesicle fusion. Blocking that entry reduces transmitter release even though the impulse has reached the terminal." }, { "chapter": "Coordination & Control", "id": "applied-stimulus-frequency", "difficulty": "Standard", "stem": "A stronger stimulus produces more action potentials per second in the same sensory axon. The height of individual action potentials stays approximately constant. This illustrates:", "options": [ "Continuous graded conduction along the entire axon", "Larger action potentials encoding every stronger stimulus", "A complete loss of the refractory period", "Stimulus intensity encoded mainly by impulse frequency in that axon" ], "answer": 3, "explanation": "Action potentials are approximately all-or-none events. Within the axon’s operating limits, a stronger stimulus can increase frequency rather than individual impulse amplitude." } ] }