Which one of the following is not a component of the diffusion membrane for gas exchange in the lungs?

The diffusion membrane in the lungs is responsible for the exchange of oxygen and carbon dioxide between the air in the lungs and the blood in the capillaries. It consists of three major layers: the thin squamous epithelium of alveoli, the endothelium of blood capillaries, and the basement membrane in between them.

The thin squamous epithelium of alveoli allows for the diffusion of gases between the air and the blood, while the endothelium of blood capillaries facilitates the transport of gases in the blood. The basement membrane provides structural support and helps to maintain the integrity of the diffusion membrane.

However, there is no cuboidal epithelium in the alveoli, as the alveoli are lined with a single layer of thin squamous epithelial cells.