Physiological barriers that prevent microbial growth exclude

Options

A. Mucus in urogenital tract
B. Acid in stomach
C. Saliva in mouth
D. Tears in eyes

Answer

To solve the question about physiological barriers that prevent microbial growth, we need to analyze each option provided and determine which one does not fit as a physiological barrier.

### Step-by-Step Solution:

1. **Understanding Physiological Barriers**: Physiological barriers are natural defenses in the body that help prevent the growth and proliferation of microbes. Common examples include mucus, stomach acid, saliva, and tears, among others.

2. **Evaluating the Options**:
- **Option 1: Mucus in urogenital tract**: Mucus serves as a barrier by trapping pathogens and preventing their entry. This is a physiological barrier.
- **Option 2: Acid in stomach**: The stomach produces hydrochloric acid, which has a very low pH (around 1.5 to 3.5). This acidic environment is hostile to many microbes, making it a physiological barrier.
- **Option 3: Saliva in Mouth**: Saliva contains enzymes and has a pH that can inhibit microbial growth (around 6.2 to 7.6). It also acts as a barrier against pathogens, thus it is a physiological barrier.
- **Option 4: Tears in Eye**: Tears contain lysozyme, an enzyme that can break down bacterial cell walls, providing a protective barrier against infections. This is also a physiological barrier.

3. **Identifying the Excluded Option**: After evaluating all options, we find that all options listed (mucus, stomach acid, saliva, and tears) are indeed physiological barriers. Therefore, the question asks for the one that does not fit, which is **Option 1: Mucus in urogenital tract**.

### Final Answer:
The physiological barrier that prevents microbial growth that is excluded is **Option 1: Mucus in urogenital tract**.