Which of the following statements about dialysis is INCORRECT ?

Options

A. Blood drained from a convenient artery is pumped into a dialysing unit after adding an anticoagulant like heparin.
B. The dialysing unit contains a coiled cellophane tube surrounded by a dialysing fluid .
C. The cleared blood is pumped back to the body through a vein after adding anti-heparin to it .
D. The dialysing fluid have the exactly the same composition as that of plasma .

Answer

To determine which statement about dialysis is incorrect, we can analyze each option based on our understanding of the dialysis process.

### Step-by-Step Solution:

1. **Understanding Dialysis**:
- Dialysis is a medical procedure used to remove waste products and excess fluid from the blood when the kidneys are not functioning properly.

2. **Analyzing the Statements**:
- **Statement 1**: "Blood drained from a convenient artery is pumped into the dialysing unit after adding an anticoagulant like heparin."
- This statement is **true**. Heparin is indeed used to prevent blood clotting during the dialysis process.

- **Statement 2**: "The dialysing unit contains a coiled cellophane tube surrounded by a dialysing fluid."
- This statement is **true**. The dialysing unit is designed with a coiled cellophane tube that allows for the exchange of waste products between the blood and the dialysing fluid.

- **Statement 3**: "The cleared blood is pumped back to the body through a vein after adding antiheparin to it."
- This statement is **true**. After the dialysis process, antiheparin is added to the blood before it is returned to the patient's body to counteract the effects of heparin.

- **Statement 4**: "The dialysing fluid has exactly the same composition as that of plasma."
- This statement is **incorrect**. The dialysing fluid is formulated to have a similar composition to plasma but does not contain nitrogenous wastes, which are the substances being removed from the blood.

3. **Conclusion**:
- The incorrect statement about dialysis is that the dialysing fluid has exactly the same composition as that of plasma. This is false because the dialysing fluid is specifically designed to lack nitrogenous wastes.

### Final Answer:
The incorrect statement about dialysis is: "The dialysing fluid has exactly the same composition as that of plasma."

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