Distal convoluted tubule

4. Distal convoluted tubule. This final segment of the nephron lies in the cortex. Its epithelial lining is low cuboidal, with no brush border, making its lumen appear wider. Its lining cells are more basophilic than those lining the proximal convoluted tubules. The lateral cell boundaries are indistinct as a result of extensive lateral membrane interdigitations with their neighbors. The distal tubule epithelium forms a disk of tightly packed columnar cells called a macula densa at the point near the vascular pole of a renal corpuscle where it contacts an afferent arteriole. This disk may monitor the osmolarity of the fluid in the tubule lumen

5. Cortical and juxtamedullary nephrons, renal corpuscles are found throughout the cortex. While most belong to the cortical nephrons, the 15% closest to the medulla belong to the juxtamedullary nephrons. The latter group has short thick descending limbs and longer thin limbs that extend deeper into the medulla. The juxtamedullary nephrons bear the primary responsibility for setting up the osmotic gradient in the medulla.