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Understanding Spirometry and Lung Volumes

Jan 26, 2025

GCSE PE Spirometry and Lung Volumes

Introduction

  • Focus on understanding spirometer trace for exams.
  • Spirometer: Device used to measure lung volumes.

Types of Lung Volumes

  1. Tidal Volume (TV)

    • Breathing at rest.
    • Amount of air during normal inhalation while resting.
    • Illustrated by small dips in spirometer trace.
    • Increases during exercise to take in more oxygen and expel more CO2.
  2. Inspiratory Reserve Volume (IRV)

    • Extra air inhaled on top of tidal volume.
    • Forced inhalation beyond normal resting breaths.
  3. Expiratory Reserve Volume (ERV)

    • Extra air exhaled on top of tidal volume.
    • Forced exhalation beyond normal breaths.
  4. Residual Volume (RV)

    • Air remaining in lungs after exhalation.
    • Constant, never changes regardless of inhalation or exhalation depth.

Spirometer Trace at Rest vs. Exercise

  • At rest: Normal tidal volume with small wave patterns.
  • During exercise:
    • Tidal volume increases.
    • Inspiratory and expiratory reserve volumes decrease.
    • Larger breathing volumes due to increased oxygen intake and CO2 expulsion.

Conclusion

  • Understanding these lung volumes is crucial for interpreting spirometer traces in exams.
  • Encouragement to ask questions for clarifications.
  • Best wishes for exam preparations.