Respiration Lab: Lungs, Ventilation, and Gas Exchange
Adjust breathing rate, tidal volume, exercise demand, and lung efficiency to observe oxygen saturation, CO2 removal, and ventilation.
Biology · Grade 9
Balance ventilation with body oxygen demand
Change breathing pattern, exercise level, airway resistance, and lung efficiency to see oxygen uptake and carbon dioxide removal.
Hit Run, then drag the diaphragm ↓ for a deeper breath — watch SpO2 respond. Stop the animation and drag to see how tidal volume controls the diaphragm position.
Slide Exercise demand to max — body needs more O2. Raise breathing rate or tidal volume until SpO2 stays above 95%. What is the minimum combination that works?
Set rate to 36/min with low exercise. SpO2 stays high but CO2 balance goes negative. This is hyperventilation — why does it cause dizziness even with enough O2?
Aerobic: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP. O₂ uptake 0.24 L/min, RQ 2.69 (0.7–1.0 normal). Rate matched by chemoreceptors.
Lab task
Increase exercise demand, then adjust breathing rate and tidal volume until oxygen saturation returns above 95%.
Observation rule
Effective gas exchange depends on alveolar ventilation and lung surface efficiency. Fast shallow breaths may move less useful air than slower deeper breaths.
What to prove in this lab
- Relate breathing rate and tidal volume to minute ventilation.
- Explain how exercise demand changes oxygen uptake and carbon dioxide production.
- Use oxygen saturation and CO2 balance to identify effective or stressed gas exchange.