Solution. 1  This species has a 2â charge on it, so it is an anion. Anions are named using the stem of the element name with the suffix -ide added. 2  Because this species has no charge, it is an atom in its elemental form. This is cobalt. 3  In this case, there is a 2+ charge on the atom, so it is a cation.
1. 2. 3. The walls of the alveoli are composed of a single layer of flattened epithelial cells, as are the walls of the capillaries, so gases need to diffuse through just two thin cells. The alveoli walls are kept moist by water diffusing from the surrounding cells.he walls of the alveoli are composed of a single layer of flattened epithelial cells, as are the walls of the capillaries, so gases need to diffuse through just two thin cells. The alveoli walls are kept moist by water diffusing from the surrounding cells.
In summary, gas exchange is the movement of oxygen into the blood and carbon dioxide out of the blood across the respiratory membrane in the lungs. This respiratory surface, also known as the respiratory membrane, includes the alveolar epithelial cells as well as the pulmonary capillary endothelial cells.his large number of alveoli greatly increases the surface area for gas exchange. Now, the total surface area of alveoli is about 140 square meters or 1,500 square feet. Wow! That's about the size of a tennis court. So if you wonder why we have alveoli, well, now you know.