In lungs there is definiteexchange of ions between RBC and plasma. Removal of `CO_(2)` from blood involves

Options

A. Influx of `Cl^(-)` ions into RBC
B. Influx of `HCO_(3)^(-)` ions into RBC
C. Efflux of `Cl^(-)` ions into RBC
D. Efflux of `HCO_(3)^(-)` ions into RBC

Answer

To answer the question regarding the removal of CO2 from blood and the exchange of ions between red blood cells (RBC) and plasma, we can break down the process step-by-step:

### Step-by-Step Solution:

1. **Understanding CO2 Transport**:
- Carbon dioxide (CO2) produced by tissues enters the bloodstream and is transported to the lungs for removal.

2. **Role of Red Blood Cells (RBC)**:
- In the blood, CO2 can exist in three forms: dissolved in plasma, bound to hemoglobin in RBCs, and as bicarbonate ions (HCO3⁻).

3. **Formation of Bicarbonate**:
- Inside the RBC, CO2 combines with water (H2O) to form carbonic acid (H2CO3) through the action of the enzyme carbonic anhydrase.
- Carbonic acid then dissociates into bicarbonate (HCO3⁻) and hydrogen ions (H⁺).

4. **Chloride Shift**:
- To maintain electrical neutrality during the formation of bicarbonate, chloride ions (Cl⁻) move from the plasma into the RBCs. This process is known as the chloride shift.
- As bicarbonate ions leave the RBC and enter the plasma, chloride ions move in to balance the charge.

5. **Transport to the Lungs**:
- The bicarbonate ions are transported in the plasma to the lungs.
- When blood reaches the lungs, bicarbonate re-enters the RBCs, and CO2 is released from the bicarbonate, allowing it to diffuse into the alveoli for exhalation.

6. **Removal of CO2**:
- The removal of CO2 from the blood involves the conversion of bicarbonate back to CO2, which is then expelled from the body during respiration.

### Summary:
The removal of CO2 from blood involves the conversion of bicarbonate back to CO2 in the lungs, facilitated by the chloride shift, where chloride ions move into RBCs from the plasma to maintain ionic balance.