Factor that helps in formation of oxyhaemoglobin in the alveoli is

Options

A. high `pCO_2`
B. high `pO_2 `
C. higher `H^+` concentration
D. all of these

Answer

To determine the factor that helps in the formation of oxyhemoglobin in the alveoli, we need to consider the following steps:

### Step-by-Step Solution:

1. **Understanding Oxyhemoglobin Formation**: Oxyhemoglobin is formed when oxygen (O2) binds to hemoglobin (Hb) in the blood. This process primarily occurs in the alveoli of the lungs, where gas exchange takes place.

2. **Identifying Key Factors**: The formation of oxyhemoglobin is influenced by several factors, including:
- The partial pressure of oxygen (pO2)
- The partial pressure of carbon dioxide (pCO2)
- The concentration of hydrogen ions (H+)
- Temperature

3. **Analyzing Partial Pressure of Oxygen**: A high partial pressure of oxygen in the alveoli is essential for the formation of oxyhemoglobin. This is because a higher concentration of oxygen increases the likelihood of oxygen molecules binding to hemoglobin.

4. **Considering Partial Pressure of Carbon Dioxide**: For optimal formation of oxyhemoglobin, the partial pressure of carbon dioxide should be low. High levels of CO2 can lead to a decrease in pH (increased H+ concentration), which can hinder the binding of oxygen to hemoglobin.

5. **Evaluating Hydrogen Ion Concentration**: A low concentration of hydrogen ions (H+) is also favorable for oxyhemoglobin formation. An increase in H+ concentration (lower pH) can reduce hemoglobin's affinity for oxygen, making it less likely to bind.

6. **Conclusion**: Among the given options, the factor that significantly helps in the formation of oxyhemoglobin in the alveoli is the high partial pressure of oxygen (pO2). Therefore, the correct answer is the option that states "high partial pressure of O2".

### Final Answer:
The factor that helps in the formation of oxyhemoglobin in the alveoli is **high partial pressure of O2**.

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