In the medullary ray, there are parallel arrays of tubules, shown in HA7 in longitudinal section. Note the similarities in morphology between the PCT in the cortex (left) and the descending thick limb (DTL) in the medullary ray (HA7, DTL). Both have irregularly shaped cells and occluded lumens. By comparison, the ascending thick limb (ATL) (HA7, ATL) has a larger lumen and more irregularly spaced nuclei than the collecting tubule. The cells of the collecting tubule vary in height. Near the capsule, the collecting tubule cells are cuboidal (HA7, CT). The cells of the collecting tubule have clear lateral cell borders and domed apices.