Which statement is incorrect?

Options

A. Mast cells and basophils secrete histamine and heparin
B. Mast cells are smaller than basophils with a bilobed nucleus.
C. Mast cells are long lived, basophils are short lived.
D. Mast cells are relatively sessile, basophils are mobile.

Answer

To determine which statement is incorrect regarding mast cells and basophils, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze the First Statement**:
- The first statement claims that mast cells and basophils secrete histamine and heparin.
- This statement is true as both mast cells and basophils are known to release these substances, which are involved in allergic reactions.

2. **Analyze the Second Statement**:
- The second statement suggests that mast cells are smaller than basophils and have a bilobed nucleus.
- This statement is incorrect. Mast cells typically range from 16 to 20 micrometers in size, while basophils are smaller, measuring about 12 to 15 micrometers. Therefore, this statement is false.

3. **Analyze the Third Statement**:
- The third statement indicates that mast cells are long-lived and basophils are short-lived.
- This statement is true. Mast cells can survive for long periods, while basophils have a shorter lifespan.

4. **Analyze the Fourth Statement**:
- The fourth statement states that mast cells are relatively sessile (stationary) and basophils are mobile.
- This statement is also true. Mast cells are typically found in tissues and do not move, while basophils circulate in the bloodstream and can migrate to sites of infection or inflammation.

5. **Conclusion**:
- After analyzing all the statements, the second statement is identified as incorrect.

### Final Answer:
The incorrect statement is: "Mast cells are smaller than basophils with a bilobed nucleus."

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