Exchange of Gases at the Level of Alveoli

Topics Covered:

What is diffusion?

How is oxygen transported from alveoli to tissues?

What is the Bohr effect?

What is the Haldane effect?

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1. What is Diffusion?

Diffusion of gases occurs from an area of higher partial pressure to an area of lower partial pressure, until equilibrium is reached between the two regions.

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2. How is Oxygen Transported from Alveoli to Tissues?

• About 3% of oxygen is transported in a dissolved.        state in plasma.

• The remaining 97% binds to hemoglobin present in        red blood cells (RBCs).

• Hemoglobin acts as the respiratory carrier.

   It has a high affinity for oxygen (O₂) and combines       with it to form oxyhemoglobin.

• One molecule of hemoglobin (Hb) contains four Fe²⁺ ions, each of which can bind to one molecule of    oxygen.

• Oxyhemoglobin is transported from the lungs to the     tissues, where it readily dissociates to release O₂.

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3. What is the Bohr Effect?

The Bohr effect refers to the shift in the oxyhemoglobin dissociation curve due to changes in the partial pressure of carbon dioxide (CO₂) in the blood.

As CO₂ increases, hemoglobin's affinity for oxygen decreases, making it easier to release O₂ to tissues.

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4. What is the Haldane Effect?

The Haldane effect is the opposite of the Bohr effect.

It describes how hemoglobin’s affinity for CO₂ decreases in response to increased oxygen concentration.

In simple words:

Bohr: CO₂ badhe to O₂ chhodega

Haldane: O₂ badhe to CO₂ chhodoga