Physiological barriers of innate immunity includes

Options

A. Skin
B. Saliva in mouth
C. PMNL cell
D. Interferons

Answer

To solve the question regarding the physiological barriers of innate immunity, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Innate Immunity**:
- Innate immunity is the first line of defense against pathogens and is present from birth. It includes various barriers that protect the body from infections.

2. **Identify Types of Barriers**:
- Innate immunity can be categorized into four types of barriers: physical barriers, physiological barriers, cellular barriers, and cytokine barriers.

3. **Differentiate Between Barrier Types**:
- **Physical Barriers**: These include structures like skin and mucous membranes. They act as the first line of defense but are not physiological barriers.
- **Physiological Barriers**: These include bodily secretions that help to inhibit pathogen growth. Examples are saliva, mucus, and gastric secretions.
- **Cellular Barriers**: These involve immune cells such as neutrophils and macrophages that actively fight infections.
- **Cytokine Barriers**: This includes proteins like interferons that help to signal and protect cells from viral infections.

4. **Evaluate the Options**:
- The question asks specifically for physiological barriers.
- Saliva in the mouth is a physiological barrier as it contains enzymes and antibodies that help to neutralize pathogens.
- Other options such as PNML cells and interferons are not physiological barriers but rather cellular and cytokine barriers, respectively.

5. **Conclusion**:
- Based on the evaluation, the correct answer is that saliva in the mouth is a physiological barrier of innate immunity.

### Final Answer:
- The physiological barriers of innate immunity include **saliva in the mouth**.