These heads are polar, they will point inward. And these hydrophobic tails, nonpolar tails, will basically aggregate in the middle. So this section here is known as the intermembrane space, the section between the outside and our inside. We have the outer membrane region as well as the inner membrane region. And the entire structure of our cell membrane is called the phosphol lipid bilayer. So two layers of phosphol lipids are arranged in the following manner.