Breathing and Exchange of Gases

Biology · Class 11

Simulation · Biology · Class 11

Reading a spirometer trace

"Reading a spirometer trace" is a free, interactive Class 11 Biology simulation for NEET, built on the NCERT section "Respiratory volumes and capacities" in Breathing and Exchange of Gases. A live spirometer trace of quiet and forced breaths; drag brackets over the trace to build IC, EC, FRC, VC and TLC from TV, IRV, ERV and RV. NEET has asked about this idea 5 times in 10 years of papers.

From the lesson Respiratory volumes and capacities in Breathing and Exchange of Gases. Change the values and watch what happens.

Reading a spirometer traceBiology · Class 11

What it shows

NCERT §14.2.1

A live spirometer trace of quiet and forced breaths; drag brackets over the trace to build IC, EC, FRC, VC and TLC from TV, IRV, ERV and RV.

Controls

4 to try

  • Buttonquiet breath / forced in / forced out
  • SliderTV 300–800 mL
  • SliderRV 800–1500 mL
  • Dragbracket ends on the trace

Try this

Bracket the vital capacity correctly on the trace (the check rejects any bracket that includes RV)

Common mistake

Residual volume is part of vital capacity.

In NEET

10 years of papers

Asked 5 times in 10 years of NEET.

See the past questions: Breathing and Exchange of Gases (chapter)

The idea behind it

NCERT §14.2.1

  • Tidal Volume (TV): the air breathed in or out in one normal breath, about 500 mL. A healthy person therefore moves roughly 6000–8000 mL of air per minute.
  • Inspiratory Reserve Volume (IRV): the extra air that can be forcibly inhaled after a normal inspiration, on average 2500–3000 mL.
  • Expiratory Reserve Volume (ERV): the extra air that can be forcibly exhaled after a normal expiration, on average 1000–1100 mL.
  • Residual Volume (RV): the air the lungs still hold even after a forcible expiration, on average 1100–1200 mL.
  • Inspiratory Capacity (IC) = TV + IRV: total air that can be inhaled after a normal expiration.
  • Expiratory Capacity (EC) = TV + ERV: total air that can be exhaled after a normal inspiration.
  • Functional Residual Capacity (FRC) = ERV + RV: air left in the lungs after a normal expiration.
  • Vital Capacity (VC) = ERV + TV + IRV: the greatest volume of air that can be breathed in following a forced expiration, or breathed out following a forced inspiration.
  • Total Lung Capacity (TLC) = VC + RV (equivalently RV + ERV + TV + IRV): all the air the lungs can hold at the end of a forced inspiration.

Questions

4 answers

What does the "Reading a spirometer trace" simulation show?
A live spirometer trace of quiet and forced breaths; drag brackets over the trace to build IC, EC, FRC, VC and TLC from TV, IRV, ERV and RV.
What mistake does the "Reading a spirometer trace" simulation fix?
A common mistake it clears up: residual volume is part of vital capacity.
Has NEET asked about this idea?
Yes. NEET has asked about this idea 5 times in 10 years of papers.
Is this simulation free?
Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Respiratory volumes and capacities" in Breathing and Exchange of Gases (Class 11 Biology).

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