What are the barriers of innate immunity?

Options

A. Physical
B. Physiological
C. Cellular
D. All of the above

Answer

### Step-by-Step Text Solution

1. **Understanding Innate Immunity**: Innate immunity is the body's first line of defense against pathogens and is present from birth. It is also referred to as inborn immunity.

2. **Types of Barriers in Innate Immunity**: There are four main types of barriers in innate immunity:
- **Physical Barriers**: These include structures that physically block pathogens from entering the body. Examples are:
- Skin: Acts as a protective layer.
- Cilia: Tiny hair-like structures in the respiratory tract that help trap and expel pathogens.
- Eyelashes: Help prevent dust and pathogens from entering the eyes.

- **Physiological Barriers**: These involve biochemical processes that help eliminate pathogens. Examples include:
- Saliva: Contains enzymes that can break down bacteria.
- Hydrochloric Acid (HCl) in the stomach: Destroys pathogens that enter through food and drink.

- **Cellular Barriers**: These consist of immune cells that respond to pathogens. Key components include:
- White Blood Cells (WBCs): Such as neutrophils and lymphocytes, which actively fight infections.

- **Cytokine Barriers**: These involve signaling proteins that help regulate immune responses. An important example is:
- Interferons: Proteins that inhibit viral replication and help protect cells from viral infections.

3. **Conclusion**: All of the above barriers—physical, physiological, cellular, and cytokine—are crucial components of innate immunity. Therefore, the correct answer to the question is that all of these are barriers of innate immunity.