Yes, epithelial cells do have a free surface. This characteristic is one of the defining features of epithelial tissue. Epithelial cells are tightly packed together and form continuous sheets that cover the surfaces of the body, both inside and out.
The free surface, also known as the apical surface, faces the body cavity, an internal organ, or the exterior of the body. This positioning allows epithelial tissue to perform several crucial functions, such as absorption, secretion, and protection. The opposite side of the epithelial layer is attached to a basement membrane, which anchors it to underlying connective tissues.
This structure is particularly important in various organs and systems. For example, in the skin, the free surface acts as a barrier to protect against environmental damage, while in the lining of the intestines, it plays a vital role in nutrient absorption.