Histamine is secreted by

Options

A. Neutrophils
B. Basophils
C. Leukocytes
D. Monocytes

Answer

**Step-by-Step Solution:**

1. **Understanding Histamine**: Histamine is a chemical that acts as a potent vasodilator, which means it helps to widen blood vessels. It is formed through the decarboxylation of the amino acid histidine.

2. **Source of Histamine**: Histamine is primarily released by mast cells in response to specific antigens. Mast cells are a type of immune cell that are found in various tissues, especially in connective tissues of the skin and respiratory tract, as well as around blood vessels.

3. **Evaluating the Options**:
- **Neutrophils**: These are a type of white blood cell (WBC) that plays a crucial role in fighting infections. They do not secrete histamine, so this option is incorrect.
- **Basophils**: These are another type of WBC that are involved in immune responses, particularly in allergic reactions. Basophils release histamine from their granules during these reactions, making this option correct.
- **Leukocytes**: This term refers to white blood cells in general. While they play a role in the immune system, they do not specifically secrete histamine, so this option is incorrect.
- **Monocytes**: These are a type of WBC that can differentiate into macrophages and dendritic cells. They are involved in immune responses but do not secrete histamine, making this option incorrect.

4. **Conclusion**: After evaluating all the options, the correct answer is that histamine is secreted by **basophils**.

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