Frequency Map (NEET 2018–2025)
| Topic Area | Approx. NEET Questions | Difficulty | Key Years |
|---|---|---|---|
| CO2 transport percentages (70/23/7) | 4–5 Qs | Medium | 2019, 2022 |
| Residual Volume definition | 3–4 Qs | Medium | 2020, 2023 |
| Inspiration muscle groups | 3–4 Qs | Easy-Medium | 2018, 2021 |
| Bohr effect — right/left shift factors | 3–4 Qs | Medium-Hard | 2019, 2023, 2024 |
| Lung capacity formulas (VC, TLC, FRC) | 3–4 Qs | Medium | Multiple years |
| Alveolar diffusion membrane layers | 2–3 Qs | Easy | 2020, 2022 |
| Respiratory disorders (emphysema, asthma) | 2–3 Qs | Medium | 2021, 2024 |
| Chloride shift / Hamburger's phenomenon | 2–3 Qs | Medium | 2019, 2022 |
| O2 transport as oxyhaemoglobin (97%) | 2 Qs | Easy | 2018, 2021 |
| Pneumotaxic centre / medullary centre | 1–2 Qs | Medium | 2023 |
Most Common NEET Question Patterns
Pattern 1: "The maximum amount of CO2 transported in blood is as..." → Answer always: Bicarbonate ions / HCO3– (70%)
Pattern 2: "Residual volume is the air remaining after..." → Answer: Maximum FORCED expiration (NOT normal expiration = FRC)
Pattern 3: "Which muscles contract during normal quiet inspiration?" → Answer: Diaphragm + External intercostals (NOT internal intercostals)
Pattern 4: "Which factor does NOT shift the O2–Hb curve to the right?" → Answer: Decreased temperature / increased pH / decreased CO2 (any one of these)
Pattern 5: "The formula for Vital Capacity is..." → Answer: TV + IRV + ERV (excludes RV)
Pattern 6: "Assertion-Reason on passive expiration" → Correct: Quiet expiration is passive; Reason: elastic recoil
High-Yield Concepts to Never Forget
- BCD = 70-23-7 (CO2 transport)
- RV ≠ FRC (RV = after max forced; FRC = after normal)
- VC excludes RV; TLC includes RV
- DEx = Diaphragm + External intercostals = inspiration
- Pons (pneumotaxic) = limits inspiration; Medulla = initiates rhythm
- Right shift = lower O2 affinity = more O2 released (not retained)