Most Tested Topics (Based on HP-04 Source + NEET History)
| Rank | Topic | Years Appeared | Question Type |
|---|---|---|---|
| 1 | GFR value and urine output paradox | 2019, 2022 | Numerical/conceptual — "How much urine/day?" trap |
| 2 | Loop of Henle permeability (descending vs ascending) | 2020, 2023 | Conceptual — mixed-up permeability options |
| 3 | Excretion mode classification (organism matching) | 2018, 2021 | Organism → excretion type or vice versa |
| 4 | RAAS cascade sequence | Multiple years | Sequence-based, A/R questions |
| 5 | Hormonal regulation (ADH vs Aldosterone vs ANF) | Every year | Comparison, "which hormone does X" |
| 6 | Nephron segment functions | Every year | Table-matching, function identification |
| 7 | Counter-current mechanism | 2020, 2022, 2023 | Mermaid-style process questions |
| 8 | Disorders (Uremia, Glomerulonephritis, Calculi) | Every 2 years | Clinical scenario → diagnosis |
High-Yield Question Formats
- Assertion-Reason — Very common for ADH mechanism, RAAS sequence, loop permeability.
- Organism-matching — Frog, tadpole, marine fish, shark trap questions.
- Numerical — GFR × time = filtrate → 99% reabsorbed → urine output.
- Diagram-based — Nephron segments, kidney cross-section, identify structures.
- Hormonal effect — "Which hormone would increase/decrease in scenario X?"
Revision Priority Matrix
- Must know (3+ questions/year): GFR = 125 mL/min, 1.5 L urine/day, 99% reabsorbed; Loop of Henle permeability; Frog/tadpole distinction; ADH vs Aldosterone mechanism.
- Important (1–2 questions/year): RAAS cascade; ANF source and trigger; Ornithine cycle location; Dialysis fluid composition.
- Occasionally tested: Juxtamedullary vs cortical nephrons; vasa recta function; PTH role in DCT; renal calculi composition.
Strategy
- Learn organisms by habitat, not just name (aquatic = ammonotelic; terrestrial = usually ureotelic/uricotelic).
- For permeability questions: write "D = Drinks water, A = Allows salts out" before answering.
- For numerical questions: always calculate filtrate first (180 L), then apply 99% rule.
- For hormonal questions: think "what problem is being solved?" — dehydration (ADH), low BP (RAAS + aldosterone), high volume (ANF).