NCS Neurologic Pathophysiology 3

Question 1

The ischemic penumbra surrounding a core infarct is clinically significant because it represents tissue that is:

Accepted Answer

Functionally impaired but potentially salvageable with timely reperfusion

Answer

The penumbra has reduced blood flow (20–50 mL/100g/min) sufficient to maintain membrane integrity temporarily but not function; reperfusion within the therapeutic window can rescue this tissue.

Question 2

Watershed (borderzone) infarctions typically occur in which clinical scenario?

Accepted Answer

Severe systemic hypotension causing hypoperfusion at arterial boundary zones

Answer

Watershed zones at the periphery of major arterial territories receive the least perfusion pressure and are first to infarct when systemic blood pressure drops precipitously.

Question 3

Diffuse axonal injury (DAI) following TBI is caused primarily by:

Accepted Answer

Rotational acceleration-deceleration forces shearing axons at white-gray matter interfaces

Answer

Rotational and angular acceleration-deceleration forces generate shear-strain at sites where tissue density changes (white-gray interfaces), physically disrupting axonal cytoskeleton and transport.

Question 4

Central cord syndrome following hyperextension cervical injury characteristically spares which function?

Accepted Answer

Lower extremity motor function

Answer

The corticospinal tract is somatotopically organized with cervical fibers medially and sacral fibers laterally; central hemorrhage/edema damages medial fibers first, sparing leg function more than arm function.

Question 5

Cerebral autoregulation maintains constant CBF over a mean arterial pressure (MAP) range of approximately:

Accepted Answer

50–150 mmHg

Answer

Intact cerebral autoregulation maintains relatively constant CBF (~50 mL/100g/min) across MAP of 50–150 mmHg through arteriolar vasoconstriction and dilation; outside this range, CBF becomes pressure-passive.

(NCS) Neurologic Clinical Specialist Practice Test

(NCS) Neurologic Clinical Specialist Practice Test

NCS Neurologic Pathophysiology 3