How are epithelial tissues classified?

• A. By their ability to contract and generate force
• B. By the shape of cells and the number of cell layers
• C. By the type of extracellular matrix they produce
• D. By the presence of blood vessels and nerve endings

Answer: (B)

Verified step by step guidance

1. Understand the basic function of epithelial tissues: Epithelial tissues serve as protective layers covering surfaces and lining cavities in the body. They are involved in absorption, secretion, and sensation.
2. Identify the criteria for classification: Epithelial tissues are classified based on two main criteria: the shape of the cells and the number of cell layers.
3. Explore cell shapes: Epithelial cells can be squamous (flat and scale-like), cuboidal (cube-shaped), or columnar (tall and column-like). These shapes help determine the specific function of the epithelial tissue.
4. Examine cell layers: Epithelial tissues can be simple (a single layer of cells) or stratified (multiple layers of cells). Simple epithelia are typically involved in absorption and filtration, while stratified epithelia provide protection.
5. Consider the incorrect options: Epithelial tissues are not classified by their ability to contract (a characteristic of muscle tissue), the type of extracellular matrix they produce (more relevant to connective tissues), or the presence of blood vessels and nerve endings (epithelial tissues are avascular and rely on diffusion from underlying tissues).