part of nephron epithelium development descending thin limb development long nephron development long descending thin limb development The process whose specific outcome is the progression of the long descending thin limb over time, from its formation to the mature structure. The long descending thin limb is the descending thin limb of a long nephron that has a squamous epithelial morphology. The long descending limb starts in the inner stripe of the outer medulla and extends into the inner medulla. GO:0072064 2010-01-25T04:13:17Z mah biological_process