About seven percent of carbon dioxide is transported to the lungs

Options

A. as carbamino compounds through RBC
B. in a dissolved state through the plasma
C. as bicarbonate ions through RBC
D. as bicarbonate ions through the plasma

Answer

To solve the question regarding the transportation of carbon dioxide (CO2) to the lungs, we will analyze the different forms in which CO2 is transported in the bloodstream.

### Step-by-Step Solution:

1. **Understanding CO2 Transportation**: Carbon dioxide is transported in the blood in three main forms:
- As bicarbonate ions (HCO3-)
- As carbamino compounds (bound to hemoglobin)
- Dissolved in plasma

2. **Percentage Breakdown**:
- Approximately **70%** of CO2 is transported as bicarbonate ions.
- About **20-25%** is transported as carbamino compounds (carbamino hemoglobin).
- Only about **7%** is dissolved in plasma.

3. **Identifying the Correct Option**: The question specifically asks about the 7% of carbon dioxide transported to the lungs. Since we have established that this percentage corresponds to CO2 that is dissolved in plasma, we can conclude that:
- The correct answer is that **7% of carbon dioxide is transported in a dissolved state through the plasma**.

4. **Final Answer**: Therefore, the correct option is **B** - in a dissolved state through the plasma.