MRCS PART A · APPLIED BASIC SCIENCES
General pathology: cell injury, recovery and death
Two selected objectives: distinguish recovery from an injury snapshot, and interpret apoptosis/necrosis evidence over time. Two foundation questions and two separately scored transfers use fictional experiments, not patient-treatment decisions. Sources checked. These are learning exercises, not a complete pathology course or calibrated exam paper.
2 topics · 4 original SBAs
1 · Ask whether the injured cell recovers
Your task: Separate a potentially reversible change from observed recovery or irreversible cellular destruction.
Does swelling alone prove that a cell has died?
No. Swelling is an injury finding, not a complete outcome. Ask what happens after the insult is removed and measure function as well as appearance.
What is stronger evidence of reversibility?
Following the same identified cell through injury and recovery of its measured function. A healthier population average could instead reflect survivors or replacement cells.
Does removing an insult guarantee recovery?
No. Recovery must be observed, not assumed. Persistent cellular destruction after removal is different from a transient reduction in measured activity.
Does one low metabolic-assay reading prove death?
Not by itself. Reduced activity can occur in injured living cells. Controls, time course, membrane findings and recovery testing help distinguish the alternatives.
What is the limit of a recovery experiment?
Recovery of the specified function supports reversibility for those tracked cells and that observation period. It does not show that every cell survived or that all functions are normal.
Can a culture result define a safe human ischaemia time?
No. Tissue, conditions and endpoints differ. No time-to-treatment threshold or clinical management rule is derived here.
2 · Describe the pattern before naming the mechanism
Your task: Recognise an apoptotic pattern and understand why a later leaky membrane does not erase earlier observations.
What pattern is consistent with apoptosis?
Cell shrinkage, condensed/fragmented nuclear material and membrane-bounded fragments, with the plasma membrane initially retaining its barrier function. Interpret the combined pattern rather than a single feature.
Does this identify the initiating pathway?
Not necessarily. Describing an apoptotic pattern does not, by itself, distinguish an intrinsic from an extrinsic trigger.
What if these cells later lose membrane integrity in culture?
An apoptotic sequence can progress to secondary necrosis when dying cells are not cleared. Earlier observations matter; the later endpoint alone does not reconstruct the route taken.
Would a single late permeability result distinguish primary from secondary necrosis?
No. It shows a compromised barrier at that time. Obtain earlier observations or additional evidence before assigning the preceding mechanism.
Is every necrotic appearance an unregulated accident?
No. A necrotic appearance does not exclude regulated cell-death mechanisms. Use appropriate mechanistic evidence before assigning a molecular subtype.
Can one biochemical marker replace the whole assessment?
No. Integrate morphology, functional observations, validated assays and timing. Cell-death nomenclature should match what was actually measured.