ENCOUNTER CLASS 6541 CERTIFICATION
SCRIPT 2026 QUESTIONS WITH ANSWERS
GRADED A+
⩥ Pathophysiology of primary brain injury. Answer: Disruption of
neurons, glial cells, axons, and blood vessels; loss of cell membrane
integrity; rupture of cellular structures; release of intracellular contents
into extracellular space; development of cytotoxic edema.
⩥ Examples of primary brain injury Answer: Head trauma with axonal
shearing and cerebral infarction from abrupt arterial occlusion.
⩥ Secondary Brain Injury Answer: Progressive neurologic damage that
develops after the primary injury.
⩥ Timeline of Secondary Brain Injury Answer: Begins minutes to hours
after injury and can continue for days to weeks.
⩥ Mechanisms of Secondary Brain Injury Answer: Ischemia, Hypoxia,
Cerebral edema, Increased ICP, Excitotoxicity, Reperfusion injury,
Inflammation.
,⩥ Cellular Consequences of Secondary Brain Injury Answer: Delayed
neuronal death, Apoptosis (programmed cell death), Necrosis from
severe ATP depletion.
⩥ Ischemia Answer: Occurs when delivery of oxygenated blood is
insufficient to meet metabolic demands of brain tissue.
⩥ Hypoxia Answer: Deficiency of oxygen at the cellular level.
⩥ Reduced blood flow Answer: Can lead to ischemia.
⩥ Reduced blood oxygen content Answer: Can lead to hypoxia.
⩥ Relationship Between Ischemia and Hypoxia Answer: Usually occur
together and both result in impaired ATP production, leading to rapid
neurologic dysfunction.
⩥ What percentage of body weight does the brain represent? Answer:
~2%
⩥ What percentage of cardiac output does the brain receive? Answer:
~15%
,⩥ What percentage of body oxygen does the brain consume? Answer:
~20%
⩥ What do neurons depend almost entirely on for energy? Answer:
Aerobic glucose metabolism
⩥ What happens to ATP levels during ischemia? Answer: ATP depletion
occurs
⩥ What is a consequence of ATP depletion in neurons? Answer: Failure
of Na⁺/K⁺-ATPase
⩥ What happens to ion gradients when ATP is depleted? Answer: Loss
of ion gradients
⩥ What is the central event in neuronal injury? Answer: Calcium
overload
⩥ What activates proteases, phospholipases, and endonucleases during
neuronal injury? Answer: Calcium overload
⩥ What leads to mitochondrial damage and cell death in neurons?
Answer: Calcium overload
, ⩥ Glutamate Answer: Primary excitatory neurotransmitter in CNS
⩥ Synaptic transmission Answer: Essential function of glutamate
⩥ Learning and memory Answer: Essential function of glutamate
⩥ Pathologic Glutamate Release Answer: Excess glutamate released into
synaptic cleft due to neuronal injury
⩥ AMPA receptors Answer: Receptors that mediate Na⁺ influx and rapid
depolarization
⩥ NMDA receptors Answer: Receptors that mediate Ca²⁺ influx and
require prior depolarization to remove Mg²⁺ block
⩥ Downstream Effects of Excess Glutamate Answer: Massive
intracellular Ca²⁺ accumulation, mitochondrial dysfunction, generation
of reactive oxygen species (ROS), reactive nitrogen species (RNS), and
nitric oxide (NO) overproduction
⩥ Vulnerable Brain Regions Answer: Cerebral cortex and hippocampus
⩥ Reperfusion Injury Answer: Tissue damage that occurs when blood
flow is restored after ischemia.