ISSA Nutritionist Practice Exam

Epithelial cells can be classified as squamous, cuboidal, or what?

1. Columnar

2. Cuboidal

3. Pseudostratified

4. Transitional

The correct answer is: Columnar

Epithelial cells can indeed be classified into three primary shapes: squamous, cuboidal, and columnar. Columnar cells are characterized by their taller, column-like structure, which allows them to specialize in functions such as secretion and absorption. This classification is essential in understanding the various roles that different epithelial tissues play in the body. Squamous epithelial cells are flat and function well in processes such as filtration and diffusion. Cuboidal epithelial cells are more about secretion and absorption, commonly found in glands and kidney tubules. Columnar cells, being taller, often have microvilli or cilia that increase surface area for absorption, making them particularly effective in the digestive tract and respiratory system. Pseudostratified cells, while featuring characteristics that might resemble multiple layers due to differing cell heights, function within a single layer. Transitional epithelium has a unique ability to stretch and is found in the urinary bladder. Therefore, while these other forms are significant in their own right, the classification of epithelial cells traditionally includes the three primary types: squamous, cuboidal, and columnar.