Histamine is secreted by

Options

A. fibroblasts
B. histocytes
C. lymphocytes
D. mast cell

Explanation

**Step-by-Step Solution:**

1. **Understanding Histamine**: Histamine is a chemical involved in the immune response, particularly in allergic reactions and inflammation. It plays a crucial role in the body's defense mechanism.

2. **Identifying the Source**: To determine which cells secrete histamine, we need to look at the cells involved in the immune response, especially during allergic reactions.

3. **Role of Mast Cells**: Mast cells are a type of white blood cell that are part of the immune system. They are primarily found in connective tissues and are known for their role in allergic reactions.

4. **Histamine Release**: When allergens (substances that can cause an allergic reaction) enter the body, they stimulate mast cells to release histamine. This release leads to various symptoms associated with allergies, such as redness, swelling, and difficulty in breathing.

5. **Conclusion**: Based on the information, we can conclude that histamine is secreted by mast cells. Therefore, the correct answer to the question is that histamine is secreted by mast cells.

**Final Answer**: Histamine is secreted by mast cells.

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