The kind of epithelium which forms the lining of alveoli
Simple squamous epithelium lines the air sacs, or alveoli, of the lungs. The alveoli are sites where air is exchanged in the lungs. Simple squamous epithelial cells in the alveoli allow oxygen from the air to enter the blood in the capillaries of the lung. Carbon dioxide, a waste product, passes across the epithelium of the alveoli to be removed from the body.