What are goblet cells?

Explanation

**Step-by-Step Text Solution:**

1. **Definition of Goblet Cells**: Goblet cells are specialized epithelial cells that produce mucus.

2. **Association with Simple Columnar Epithelium**: Goblet cells are primarily found within the simple columnar epithelium. This type of epithelium consists of elongated cells that are arranged in a single layer.

3. **Structure of Simple Columnar Epithelium**: In simple columnar epithelium, the nuclei of the cells are located near the base, and the free surface of these cells is smooth.

...