Which classification describes a single layer of flat cells?

Which classification describes a single layer of flat cells?

• A. Simple squamous epithelium
• B. Stratified squamous epithelium
• C. Simple cuboidal epithelium
• D. Pseudostratified ciliated columnar epithelium

Answer: (A)

A single layer of flat cells is described as simple squamous epithelium. Simple means one cell layer, and squamous means the cells are flattened and thin. This combination creates a very thin barrier that facilitates rapid diffusion and filtration, which is why it lines places like the walls of blood vessels and the air sacs in the lungs, as well as the membranes lining body cavities. The other options don’t match: a stratified type has multiple layers, so it isn’t a single layer; a simple cuboidal type is a single layer but with cube-shaped cells, not flat; and pseudostratified ciliated columnar appears multilayered due to nuclei at different heights and is composed of tall, column-like cells, not flat ones.

A single layer of flat cells is described as simple squamous epithelium. Simple means one cell layer, and squamous means the cells are flattened and thin. This combination creates a very thin barrier that facilitates rapid diffusion and filtration, which is why it lines places like the walls of blood vessels and the air sacs in the lungs, as well as the membranes lining body cavities. The other options don’t match: a stratified type has multiple layers, so it isn’t a single layer; a simple cuboidal type is a single layer but with cube-shaped cells, not flat; and pseudostratified ciliated columnar appears multilayered due to nuclei at different heights and is composed of tall, column-like cells, not flat ones.