A&P Lab Exam #2 Review (Respiratory Physiology)

Respiratory Physiology

Examine how the bicarbonate buffer system works in the blood. Write down the chemical formula.

What enzyme catalyzes the reaction of CO2 to bicarbonate and the reverse?

To maintain pH balance, CO₂ combines with water:

𝐶𝑂2 +𝐻2𝑂⇌𝐻2𝐶𝑂3⇌𝐻++𝐻𝐶𝑂3−CO2 +H2O⇌H2CO3⇌H++HCO3−

Catalyzed by carbonic anhydrase.

This allows CO₂ to be transported in the blood mainly as bicarbonate ions (HCO₃⁻).

Know where lung volumes are represented on a spirograph

Think about how much air is moving during tidal breathing

Tidal Volume (TV): air moved in/out normally (~500 mL).

Inspiratory Reserve Volume (IRV): max inhaled beyond normal breath.

Expiratory Reserve Volume (ERV): max exhaled beyond normal.

Residual Volume (RV): air remaining after full exhale.

Be able to explain the mechanics of normal breathing (which muscles are used and the pressure values involved in the lungs vs the outside world)

What does this mean for inspiration and expiration? How do these pressures differ to allow air to flow in or out of the lungs?

Inspiration: diaphragm and external intercostals contract → thoracic volume ↑ → lung pressure ↓ → air flows in.

Expiration: muscles relax → thoracic volume ↓ → pressure ↑ → air flows out.

Know the relationship between pressure and volume when breathing

Hint: there’s a specific physics law that governs this.

Boyle’s Law:

Pressure and volume are inversely related.

When lung volume increases, pressure decreases (air enters).

When lung volume decreases, pressure increases (air exits).