What Is the Medical Definition of Squamous Cells?

Squamous cells are flat cells that make up much of the skin and the linings of the internal organs, according to MedicineNet. They get their name because they resemble the scales of a fish or serpent.

Because simple squamous cells are flat and thin, they have a great deal of surface area, says the Davidson College Biology Department. They have a top, or apical, surface and a basolateral surface that contain the basement membrane. The nuclei of the cell are found between these two layers and are unusual in that they are shaped like ellipses.

Because squamous cells are so thin, they allow the passage of molecules such as oxygen and carbon dioxide, says the Davidson College Biology Department. This is necessary for respiration. Other ions are also allowed to move in and out of squamous cells and into the bloodstream. Simple squamous cells are found in the lungs, the kidneys and the lining of the body cavity.

Squamous cells are also stratified, according to Rutgers University. These cells provide protection for areas of the body. There are keratinized and nonkeratinized squamous epithelium. In the keratinized type, the top layer is made up of dead cells that are constantly sloughed off. This is seen in the skin. Nonkeratinized squamous epithelium is found in places that are not subject to drying out, such as the esophagus.