A tissue type that has cells touching the basement membrane but not all reaching the free surface is referred to as what?

The tissue type described, where all cells are anchored to the basement membrane but not all extend to the free surface, is known as pseudostratified epithelium. This characteristic is a defining feature of pseudostratified epithelium, as it appears to have multiple layers due to the varying heights of the cells. However, since all cells are in contact with the basement membrane, it is technically a single layer.

This type of epithelium is commonly found in the respiratory tract, where it often has cilia and is involved in the secretion of mucus and the movement of particles out of the airways. The presence of cilia on the surface helps trap and expel debris, highlighting the functional specialization of this tissue type.

In contrast, simple cuboidal epithelium and simple columnar epithelium consist of uniformly shaped cells that extend from the basement membrane to the free surface without the layered appearance, and simple squamous epithelium is made up of a single layer of flat cells, also reaching the free surface. These structures differ in function and location compared to pseudostratified epithelium, which predominantly serves specialized roles in certain organs.