What is the length of distal convoluted tubule in adults?

The distal convoluted tubule, which stas at the macula densa, is about 5 mm long. Its epithelium is lower than that of the proximal tubule, and although a few microvilli are present, there is no distinct brush border. The distal tubules coalesce to form collecting ducts that are about 20 mm long and pass through the renal coex and medulla to empty into the pelvis of the kidney at the apexes of the medullary pyramids. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 37. Renal Function & Micturition. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.