What is simple epithelium?

Simple epithelium is an epithelial tissue that comprises a single layer of epithelial cells. Every cell in the simple epithelium is in direct contact with the basement membrane.

Because it consists of only one layer of cells, the simple epithelium is relatively fragile and only found inside the body. It can be found lining the heart, blood vessels, respiratory system, body cavities, and lymph vessels. It is primarily involved in absorption and filtration. Being a thin layer gives the simple epithelium the advantage of faster and more efficient absorption and filtration.   

The simple epithelium can be further classified into three types, based on the shape of epithelial cells. 

The simple squamous epithelium is made up of a single layer of flat, thin, scale-like cells and can be found lining blood vessels and body cavities. 

The simple cuboidal epithelium is made up of a single layer of cube-like cells that have equal width, height, and depth. It can be found in glandular tissue, kidney tubules, thyroid glands, and sweat gland ducts. 

The simple columnar epithelium is composed of column-like rectangular cells packed together closely and can be found in the ducts of glands, stomach, gall bladder and intestine lining.