The thin segment is a segment of the nephron, which consists of:
Histology
The basement membrane of the thin limb in humans has very uniform nodular thickenings that form a network that surrounds the tubule and acts as a support structure that is homologous to the collenchyma in plants. Smith, RA et al. (Arch Pathol Lab Med Vol 108, May 1984) have designated these nodules "Belliveau Bodies" after Robert Belliveau the pathologist who originally described these structures. The epithelium is Simple squamous epithelium.
References
Thin segment Wikipedia(Text) CC BY-SA