Which of the following is not a secretory pa of kidney?

The secretory poion of kidney is contained largely within the coex and consists of a renal corpuscle and the secretory pa of the renal tubule. The excretory poion of this duct lies in the medulla. The renal corpuscle is composed of the vascular glomerulus, which projects into Bowman's capsule, which, in turn, is continuous with the epithelium of the proximal convoluted tubule. The secretory poion of the renal tubule is made up of the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule. The excretory poion of the nephron is the collecting tubule, which is continuous with the distal end of the ascending limb of the convoluted tubule. It empties its contents through the tip (papilla) of a pyramid into a minor calyx. Ref: Butterwoh IV J.F., Mackey D.C., Wasnick J.D. (2013). Chapter 29. Renal Physiology & Anesthesia. In J.F. Butterwoh IV, D.C. Mackey, J.D. Wasnick (Eds), Morgan & Mikhail's Clinical Anesthesiology, 5e.