11. Another question is whether it can be counted as a nephron when there is no loop of Henle ( AFAIK ). 12. The primary role of the loop of Henle is to concentrate the salt in the interstitium, the tissue surrounding the loop. 13. In contrast, the medulla is structured into medullary cones that contain nephron elements, specifically collecting ducts and loops of Henle . 14. However, they surround the loop of Henle , forming the vasa recta, only in juxtamedullary nephrons and not in cortical nephrons. 15. Overall the loop of Henle reabsorbs around 25 % of filtered ions and 20 % of the filtered water in a normal kidney. 16. It contains the renal corpuscles and the renal tubules except for parts of the loop of Henle which descend into the renal medulla. 17. "' Bartter syndrome "'is a rare inherited defect in the thick ascending limb of the loop of Henle . 18. Since the descending limb of the loop of henle consists of very leaky epithelium, the fluid inside the descending limb becomes hyperosmolar. 19. The second segment of the tubules is the loop of Henle where the reabsorption of water and ions from the urine takes place. 20. The hypertonicity of the medulla ( and therefore concentration of urine ) is determined in part by the size of the loop of Henle .
