NUR 555 Quiz 4:
Advanced Pathophysiology
Questions and Answers | 2026 Update | 100% Correct -
SNHU
August 2026
, NUR 555 Quiz 4 | Advanced Pathophysiology | SNHU 2026
Section 1: Advanced Neurological Pathophysiology (Q1-Q10)
Q1: Which pathophysiological mechanism is the primary initiator of ischemic stroke in the territory of the middle cerebral
artery (MCA)?
A. Rupture of a Charcot-Bouchard microaneurysm in the basal ganglia leading to intraparenchymal hemorrhage
B. Thromboembolic occlusion of the proximal MCA segment, most commonly originating from an atherosclerotic
plaque in the internal carotid artery
C. Reversible cerebral vasoconstriction triggered by sympathetic overactivation and catecholamine surge
D. Venous sinus thrombosis in the superior sagittal sinus causing retrograde venous congestion
Correct Answer: B
Rationale: Ischemic stroke in the MCA territory is most commonly caused by thromboembolism arising from atherosclerotic plaque
rupture in the internal carotid artery or cardiac sources (e.g., atrial fibrillation). Option A describes a hemorrhagic mechanism
(intracerebral hemorrhage), not ischemic. Option C describes reversible cerebral vasoconstriction syndrome, a distinct entity. Option
D describes cerebral venous sinus thrombosis, which produces venous infarction rather than arterial ischemia.
Q2: In Alzheimer's disease, which neurochemical change occurs earliest in the disease trajectory and is most strongly
correlated with the initial cognitive deficits?
A. Dopamine depletion in the substantia nigra pars compacta leading to bradykinesia and resting tremor
B. Loss of cholinergic neurons in the nucleus basalis of Meynert resulting in reduced acetylcholine levels in the
cerebral cortex and hippocampus
C. Demyelination of oligodendrocytes in the periventricular white matter with axonal transection
D. Accumulation of alpha-synuclein aggregates in Lewy bodies within the brainstem and cortical neurons
Correct Answer: B
Rationale: The earliest neurochemical change in Alzheimer's disease is the degeneration of cholinergic neurons in the nucleus basalis
of Meynert, which projects widely to the cerebral cortex and hippocampus, leading to acetylcholine deficiency that correlates with
memory impairment. Option A describes Parkinson's disease pathology (dopaminergic loss). Option C describes multiple sclerosis
pathology (demyelination). Option D describes Lewy body dementia or Parkinson's disease pathology (alpha-synuclein).
Q3: What is the primary pathophysiological distinction between a tonic-clonic generalized seizure and an absence seizure
at the cellular level?
A. Tonic-clonic seizures involve hyperexcitability of both cerebral hemispheres simultaneously, whereas absence
seizures originate from focal cortical irritative zones
B. Tonic-clonic seizures result from widespread neuronal depolarization with failure of inhibitory GABAergic
mechanisms, whereas absence seizures involve thalamocortical circuit dysfunction with abnormal 3-Hz
spike-and-wave discharges
C. Absence seizures are caused by excessive glutamate release in the hippocampus, while tonic-clonic seizures stem
from glycine receptor antagonism in the brainstem
D. Tonic-clonic seizures involve only excitatory NMDA receptor activation, whereas absence seizures involve only
GABA-A receptor potentiation
Correct Answer: B
Rationale: Tonic-clonic seizures involve widespread bilateral neuronal hypersynchronization with failure of both GABAergic
inhibition and excessive glutamatergic excitation. Absence seizures arise from thalamocortical loop dysfunction characterized by
3-Hz generalized spike-and-wave discharges on EEG. Option A is incorrect because absence seizures are generalized, not focal.
Option C incorrectly attributes absence seizures to hippocampal glutamate release and misidentifies tonic-clonic mechanisms. Option
D incorrectly oversimplifies both seizure types to single receptor mechanisms.
Q4: A 68-year-old patient with atrial fibrillation not on anticoagulation presents with sudden-onset left-sided hemiparesis,
left homonymous hemianopsia, and gaze preference to the right. The NIH Stroke Scale score is 18. CT angiography
demonstrates complete occlusion of the right M1 segment of the middle cerebral artery. The patient arrived 90 minutes
after symptom onset. Which pathophysiological rationale best explains the urgency of endovascular thrombectomy in this
patient?
Page 2
, NUR 555 Quiz 4 | Advanced Pathophysiology | SNHU 2026
A. The ischemic penumbra surrounding the infarct core is salvageable tissue that will irreversibly infarct if perfusion
is not restored before the collateral circulation fails, typically within 6 hours of onset
B. Endovascular thrombectomy prevents the transformation of a hemorrhagic infarction into a parenchymal
hematoma by reducing reperfusion injury through controlled catheter-based suction
C. The M1 occlusion has triggered a cytotoxic cascade that causes immediate blood-brain barrier breakdown, and
thrombectomy reverses this cascade by removing the embolic source before glutamate excitotoxicity peaks at 2 hours
D. Thrombectomy is urgent because the fibrinolytic system in the MCA territory is particularly resistant to tissue
plasminogen activator, making pharmacological reperfusion impossible in anterior circulation strokes
Correct Answer: A
Rationale: The ischemic penumbra is hypoperfused but still viable brain tissue that can be salvaged if reperfusion is achieved before
irreversible cell death occurs. Time is brain because the penumbra progressively shrinks as the infarct core expands. Option B is
incorrect because thrombectomy does not prevent hemorrhagic transformation through suction mechanics. Option C incorrectly
describes the sequence of events and overstates the reversibility of cytotoxic injury once blood-brain barrier breakdown is
established. Option D is incorrect because tPA efficacy depends on clot composition, not vascular territory, and many anterior
circulation strokes are treated with IV tPA.
Q5: A 55-year-old woman presents with progressively worsening intention tremor, scanning speech, and nystagmus over
18 months. MRI of the brain demonstrates multiple periventricular and juxtacortical T2 hyperintense lesions, some with
gadolinium enhancement. Cerebrospinal fluid analysis shows elevated IgG index with oligoclonal bands. Which
pathophysiological mechanism best explains the demyelination process in this patient's disease?
A. Direct viral cytotoxicity against oligodendrocytes causing segmental demyelination with axonal preservation in
affected white matter tracts
B. Autoimmune-mediated T-lymphocyte and macrophage attack on myelin sheaths in the central nervous system,
driven by molecular mimicry and blood-brain barrier disruption, resulting in perivenular inflammatory demyelination
C. Metabolic dysfunction of oligodendrocytes due to impaired ceramide synthesis leading to progressive failure of
myelin maintenance and secondary axonal degeneration
D. Ischemic injury to periventricular white matter from chronic cerebral hypoperfusion, causing watershed infarction
that mimics demyelinating disease on MRI
Correct Answer: B
Rationale: Multiple sclerosis involves autoimmune-mediated demyelination where autoreactive T-lymphocytes cross the blood-brain
barrier, recognize myelin antigens through molecular mimicry, and recruit macrophages that strip myelin from axons. The
perivenular distribution of inflammatory infiltrates is characteristic. Option A incorrectly attributes the mechanism to direct viral
cytotoxicity, which is the proposed mechanism in progressive multifocal leukoencephalopathy, not MS. Option C describes a
metabolic leukodystrophy mechanism. Option D describes small vessel ischemic disease, which can mimic MS on imaging but has
distinct pathophysiology and does not produce oligoclonal bands.
Q6: A 72-year-old man with a history of hypertension presents with sudden severe headache, nausea, vomiting, and
rapidly deteriorating consciousness. Non-contrast CT of the head reveals hyperdense blood in the subarachnoid cisterns,
particularly in the basal cisterns, with early ventricular extension. Which cascade of pathophysiological events poses the
greatest risk of secondary brain injury in the first 72 hours after this event?
A. Cerebral vasospasm triggered by hemoglobin breakdown products (especially oxyhemoglobin) from subarachnoid
blood, leading to delayed ischemic neurologic deficits through smooth muscle contraction and endothelial
dysfunction
B. Rapid formation of a parenchymal hematoma in the cerebellum causing acute hydrocephalus from fourth ventricle
compression and obstructive CSF flow
C. Diffuse axonal injury from shearing forces at gray-white matter junctions, triggering progressive
neuroinflammation and microglial activation over 48 to 72 hours
D. Thromboembolic propagation from the ruptured aneurysm site causing multiple distal arterial branch occlusions
and watershed infarctions
Correct Answer: A
Page 3
Advanced Pathophysiology
Questions and Answers | 2026 Update | 100% Correct -
SNHU
August 2026
, NUR 555 Quiz 4 | Advanced Pathophysiology | SNHU 2026
Section 1: Advanced Neurological Pathophysiology (Q1-Q10)
Q1: Which pathophysiological mechanism is the primary initiator of ischemic stroke in the territory of the middle cerebral
artery (MCA)?
A. Rupture of a Charcot-Bouchard microaneurysm in the basal ganglia leading to intraparenchymal hemorrhage
B. Thromboembolic occlusion of the proximal MCA segment, most commonly originating from an atherosclerotic
plaque in the internal carotid artery
C. Reversible cerebral vasoconstriction triggered by sympathetic overactivation and catecholamine surge
D. Venous sinus thrombosis in the superior sagittal sinus causing retrograde venous congestion
Correct Answer: B
Rationale: Ischemic stroke in the MCA territory is most commonly caused by thromboembolism arising from atherosclerotic plaque
rupture in the internal carotid artery or cardiac sources (e.g., atrial fibrillation). Option A describes a hemorrhagic mechanism
(intracerebral hemorrhage), not ischemic. Option C describes reversible cerebral vasoconstriction syndrome, a distinct entity. Option
D describes cerebral venous sinus thrombosis, which produces venous infarction rather than arterial ischemia.
Q2: In Alzheimer's disease, which neurochemical change occurs earliest in the disease trajectory and is most strongly
correlated with the initial cognitive deficits?
A. Dopamine depletion in the substantia nigra pars compacta leading to bradykinesia and resting tremor
B. Loss of cholinergic neurons in the nucleus basalis of Meynert resulting in reduced acetylcholine levels in the
cerebral cortex and hippocampus
C. Demyelination of oligodendrocytes in the periventricular white matter with axonal transection
D. Accumulation of alpha-synuclein aggregates in Lewy bodies within the brainstem and cortical neurons
Correct Answer: B
Rationale: The earliest neurochemical change in Alzheimer's disease is the degeneration of cholinergic neurons in the nucleus basalis
of Meynert, which projects widely to the cerebral cortex and hippocampus, leading to acetylcholine deficiency that correlates with
memory impairment. Option A describes Parkinson's disease pathology (dopaminergic loss). Option C describes multiple sclerosis
pathology (demyelination). Option D describes Lewy body dementia or Parkinson's disease pathology (alpha-synuclein).
Q3: What is the primary pathophysiological distinction between a tonic-clonic generalized seizure and an absence seizure
at the cellular level?
A. Tonic-clonic seizures involve hyperexcitability of both cerebral hemispheres simultaneously, whereas absence
seizures originate from focal cortical irritative zones
B. Tonic-clonic seizures result from widespread neuronal depolarization with failure of inhibitory GABAergic
mechanisms, whereas absence seizures involve thalamocortical circuit dysfunction with abnormal 3-Hz
spike-and-wave discharges
C. Absence seizures are caused by excessive glutamate release in the hippocampus, while tonic-clonic seizures stem
from glycine receptor antagonism in the brainstem
D. Tonic-clonic seizures involve only excitatory NMDA receptor activation, whereas absence seizures involve only
GABA-A receptor potentiation
Correct Answer: B
Rationale: Tonic-clonic seizures involve widespread bilateral neuronal hypersynchronization with failure of both GABAergic
inhibition and excessive glutamatergic excitation. Absence seizures arise from thalamocortical loop dysfunction characterized by
3-Hz generalized spike-and-wave discharges on EEG. Option A is incorrect because absence seizures are generalized, not focal.
Option C incorrectly attributes absence seizures to hippocampal glutamate release and misidentifies tonic-clonic mechanisms. Option
D incorrectly oversimplifies both seizure types to single receptor mechanisms.
Q4: A 68-year-old patient with atrial fibrillation not on anticoagulation presents with sudden-onset left-sided hemiparesis,
left homonymous hemianopsia, and gaze preference to the right. The NIH Stroke Scale score is 18. CT angiography
demonstrates complete occlusion of the right M1 segment of the middle cerebral artery. The patient arrived 90 minutes
after symptom onset. Which pathophysiological rationale best explains the urgency of endovascular thrombectomy in this
patient?
Page 2
, NUR 555 Quiz 4 | Advanced Pathophysiology | SNHU 2026
A. The ischemic penumbra surrounding the infarct core is salvageable tissue that will irreversibly infarct if perfusion
is not restored before the collateral circulation fails, typically within 6 hours of onset
B. Endovascular thrombectomy prevents the transformation of a hemorrhagic infarction into a parenchymal
hematoma by reducing reperfusion injury through controlled catheter-based suction
C. The M1 occlusion has triggered a cytotoxic cascade that causes immediate blood-brain barrier breakdown, and
thrombectomy reverses this cascade by removing the embolic source before glutamate excitotoxicity peaks at 2 hours
D. Thrombectomy is urgent because the fibrinolytic system in the MCA territory is particularly resistant to tissue
plasminogen activator, making pharmacological reperfusion impossible in anterior circulation strokes
Correct Answer: A
Rationale: The ischemic penumbra is hypoperfused but still viable brain tissue that can be salvaged if reperfusion is achieved before
irreversible cell death occurs. Time is brain because the penumbra progressively shrinks as the infarct core expands. Option B is
incorrect because thrombectomy does not prevent hemorrhagic transformation through suction mechanics. Option C incorrectly
describes the sequence of events and overstates the reversibility of cytotoxic injury once blood-brain barrier breakdown is
established. Option D is incorrect because tPA efficacy depends on clot composition, not vascular territory, and many anterior
circulation strokes are treated with IV tPA.
Q5: A 55-year-old woman presents with progressively worsening intention tremor, scanning speech, and nystagmus over
18 months. MRI of the brain demonstrates multiple periventricular and juxtacortical T2 hyperintense lesions, some with
gadolinium enhancement. Cerebrospinal fluid analysis shows elevated IgG index with oligoclonal bands. Which
pathophysiological mechanism best explains the demyelination process in this patient's disease?
A. Direct viral cytotoxicity against oligodendrocytes causing segmental demyelination with axonal preservation in
affected white matter tracts
B. Autoimmune-mediated T-lymphocyte and macrophage attack on myelin sheaths in the central nervous system,
driven by molecular mimicry and blood-brain barrier disruption, resulting in perivenular inflammatory demyelination
C. Metabolic dysfunction of oligodendrocytes due to impaired ceramide synthesis leading to progressive failure of
myelin maintenance and secondary axonal degeneration
D. Ischemic injury to periventricular white matter from chronic cerebral hypoperfusion, causing watershed infarction
that mimics demyelinating disease on MRI
Correct Answer: B
Rationale: Multiple sclerosis involves autoimmune-mediated demyelination where autoreactive T-lymphocytes cross the blood-brain
barrier, recognize myelin antigens through molecular mimicry, and recruit macrophages that strip myelin from axons. The
perivenular distribution of inflammatory infiltrates is characteristic. Option A incorrectly attributes the mechanism to direct viral
cytotoxicity, which is the proposed mechanism in progressive multifocal leukoencephalopathy, not MS. Option C describes a
metabolic leukodystrophy mechanism. Option D describes small vessel ischemic disease, which can mimic MS on imaging but has
distinct pathophysiology and does not produce oligoclonal bands.
Q6: A 72-year-old man with a history of hypertension presents with sudden severe headache, nausea, vomiting, and
rapidly deteriorating consciousness. Non-contrast CT of the head reveals hyperdense blood in the subarachnoid cisterns,
particularly in the basal cisterns, with early ventricular extension. Which cascade of pathophysiological events poses the
greatest risk of secondary brain injury in the first 72 hours after this event?
A. Cerebral vasospasm triggered by hemoglobin breakdown products (especially oxyhemoglobin) from subarachnoid
blood, leading to delayed ischemic neurologic deficits through smooth muscle contraction and endothelial
dysfunction
B. Rapid formation of a parenchymal hematoma in the cerebellum causing acute hydrocephalus from fourth ventricle
compression and obstructive CSF flow
C. Diffuse axonal injury from shearing forces at gray-white matter junctions, triggering progressive
neuroinflammation and microglial activation over 48 to 72 hours
D. Thromboembolic propagation from the ruptured aneurysm site causing multiple distal arterial branch occlusions
and watershed infarctions
Correct Answer: A
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