Kidney. Convoluted Tubules. Periodic Acid–Schiff PAS Method Royalty-Free Stock Image

Boundary between cortex and renal medulla stained with periodic acid Schiff PAS method. In the upper half of the image, there are only proximal convoluted tubules in which the PAS method allows to distinguish the outer basement membrane and the brush border bordering the lumen, while in the lower half only distal contoured tubules are seen with a lower epithelium and lacking brush border at the