Cells which secrete histamine occur in

Options

A. lungs
B. brain
C. liver
D. connective tissue

Answer

To answer the question "Cells which secrete histamine occur in," we will analyze the provided options step by step.

### Step-by-Step Solution:

1. **Understanding Histamine:**
- Histamine is a chemical involved in immune responses, regulation of stomach acid, and neurotransmission. It is primarily associated with allergic reactions and inflammatory processes.

2. **Analyzing the Options:**
- We have four options: lungs, brain, liver, and connective tissue. We need to determine where histamine-secreting cells are located.

3. **Option 1: Lungs**
- The primary function of the lungs is respiration (exchange of oxygen and carbon dioxide). They do not play a role in the secretion of histamine. Therefore, this option is incorrect.

4. **Option 2: Brain**
- The brain is responsible for controlling various functions such as memory, balance, and coordination. It does not secrete histamine. Thus, this option is also incorrect.

5. **Option 3: Liver**
- The liver is involved in detoxification, metabolism, and other vital functions. However, it does not secrete histamine. Hence, this option is incorrect as well.

6. **Option 4: Connective Tissue**
- Connective tissues are diverse and include various cell types. One of the key cell types found in connective tissue is mast cells, which are known to secrete histamine, especially during allergic reactions and inflammatory responses. Therefore, this option is correct.

7. **Conclusion:**
- The cells that secrete histamine occur in **connective tissue**.

### Final Answer:
The correct answer is **connective tissue**.

---