So the basement membrane provides an attachment point for these epithelial cells. And below the basement membrane, we have some sort of connective tissue. So we have these blood vessels, we have our capillaries, we have these veins that basically provide the nutrients to these cells and also take away the waste products that are secreted by these cells. So the side of the cell that points towards the lumen side, the cavity, is known as the apical side, while the side attached to our basement membrane, it's called the basil lateral side. Now, the basement membrane is also sometimes known as the basal lamina or the basal membrane. Now, this basement membrane acts as an attachment point for the cells.