abnormal loop of Henle morphology abnormal loop of Henle descending limb morphology 2011-10-13T09:44:50Z MA:0001679 MP:0011341 MPheno.ontology abnormal ansa nephroni descending limb morphology abnormal descending limb of Henle's loop morphology abnormal descending limb of loop of Henle morphology abnormal descending loop of Henle morphology any structural anomaly of the portion of the renal tubule that constitutes the proximal part of the loop of Henle, has low permeability to ions and urea, and is highly permeable to water; it consists of an initial short thick segment lined by low simple cuboidal epithelium and a long thin segment lined by simple squamous epithelium; however, this distinction is not as important physiologically as in the ascending limb, so often the two are treated as one structure csmith