So, as the filter travels down the tubule of the Loop of Henley, this segment is known as the descending loop of Henley. At the bottom, the filter basically changes direction and begins to travel upward. And this segment is known as the thin ascending loop of Henley. The thin part simply means the size of our epithelial cells within this section are small. These cells are thin, they're relatively small, while this is our thick ascending loop of Henley. And thick means our size of the cells is relatively large.