The leftward shift of the oxyhemoglobin dissociation curve caused by hypocarbia is known as the

The leftward shift of the oxyhemoglobin dissociation curve caused by hypocarbia is known as the

• A. Fick principle
• B. Bohr effect
• C. Haldane effect
• D. Law of Laplace

Answer: (B)

The Bohr effect describes how carbon dioxide and hydrogen ion concentration influence hemoglobin’s affinity for oxygen. When CO2 levels fall (hypocarbia), hydrogen ion concentration drops and pH rises, which increases hemoglobin’s affinity for O2. This makes the oxyhemoglobin dissociation curve shift to the left, meaning hemoglobin binds oxygen more tightly and favors loading in the lungs. In contrast, higher CO2 or lower pH (the opposite conditions) lower Hb’s affinity for O2 and shift the curve to the right, promoting oxygen release in tissues. The other options don’t describe this CO2/pH–driven change: the Fick principle relates diffusion rates and perfusion, the Haldane effect concerns how oxygenation alters CO2 carriage, and the Law of Laplace relates pressure and radius in spherical shells.

The Bohr effect describes how carbon dioxide and hydrogen ion concentration influence hemoglobin’s affinity for oxygen. When CO2 levels fall (hypocarbia), hydrogen ion concentration drops and pH rises, which increases hemoglobin’s affinity for O2. This makes the oxyhemoglobin dissociation curve shift to the left, meaning hemoglobin binds oxygen more tightly and favors loading in the lungs.

In contrast, higher CO2 or lower pH (the opposite conditions) lower Hb’s affinity for O2 and shift the curve to the right, promoting oxygen release in tissues. The other options don’t describe this CO2/pH–driven change: the Fick principle relates diffusion rates and perfusion, the Haldane effect concerns how oxygenation alters CO2 carriage, and the Law of Laplace relates pressure and radius in spherical shells.