Which epithelium is a single layer of flat cells?

Which epithelium is a single layer of flat cells?

• A. Simple cuboidal epithelium
• B. Transitional epithelium
• C. Simple squamous epithelium
• D. Simple columnar epithelium

Answer: (C)

In epithelial tissues, the name reflects both how many layers and the shape of the cells. A single layer of flat cells is described as simple squamous epithelium. The term “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 you find simple squamous lining the air sacs of the lungs, the lining of blood vessels (endothelium), and parts of the kidney where filtration occurs, as well as serous membranes. In contrast, simple cuboidal epithelium is a single row of cube-shaped cells involved more in secretion and absorption, simple columnar epithelium is a single row of tall, column-like cells often specialized for absorption and sometimes secretion, and transitional (urothelial) epithelium is stratified and highly stretchable, not a single uniform layer.

In epithelial tissues, the name reflects both how many layers and the shape of the cells. A single layer of flat cells is described as simple squamous epithelium. The term “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 you find simple squamous lining the air sacs of the lungs, the lining of blood vessels (endothelium), and parts of the kidney where filtration occurs, as well as serous membranes.

In contrast, simple cuboidal epithelium is a single row of cube-shaped cells involved more in secretion and absorption, simple columnar epithelium is a single row of tall, column-like cells often specialized for absorption and sometimes secretion, and transitional (urothelial) epithelium is stratified and highly stretchable, not a single uniform layer.