To determine how many substances from the given list are secreted by exocrine glands, we need to identify which substances are produced by these glands. Exocrine glands release their secretions through ducts to the surface of an organ or into a body cavity, while endocrine glands release their hormones directly into the bloodstream.
Let's analyze each substance in the list:
1. **Saliva**:
- Secreted by salivary glands, which are exocrine glands.
- **Conclusion**: Exocrine secretion.
2. **Oil**:
- Secreted by sebaceous (oil) glands, which are also exocrine glands.
- **Conclusion**: Exocrine secretion.
3. **Digestive Enzymes**:
- Secreted by glands in the digestive system, such as the pancreas (which has both exocrine and endocrine functions), but the digestive enzymes are secreted into the digestive tract.
- **Conclusion**: Exocrine secretion.
4. **Thyroxine**:
- Secreted by the thyroid gland, which is an endocrine gland.
- **Conclusion**: Not an exocrine secretion.
5. **FSH (Follicle Stimulating Hormone)**:
- Secreted by the anterior pituitary gland, which is an endocrine gland.
- **Conclusion**: Not an exocrine secretion.
6. **Mucus**:
- Secreted by mucous glands in various parts of the body, including the stomach, which are exocrine glands.
- **Conclusion**: Exocrine secretion.
7. **Insulin**:
- Secreted by the pancreas, but as a hormone, it is an endocrine secretion.
- **Conclusion**: Not an exocrine secretion.
8. **Earwax**:
- Secreted by ceruminous glands in the ear, which are exocrine glands.
- **Conclusion**: Exocrine secretion.
Now, let's summarize the findings:
- **Exocrine Secretions**: Saliva, Oil, Digestive Enzymes, Mucus, Earwax
- **Non-Exocrine Secretions**: Thyroxine, FSH, Insulin
Counting the exocrine secretions, we find that there are **5 substances** that are secreted by exocrine glands.
**Final Answer**: 5 substances are secreted by exocrine glands.
