Draw a labelled diagram showing reabsorption and secretion of major substances at different parts of the nephron.

(N/A) Reabsorption:
$A$ comparison of the volume of the filtrate formed per day $(180 \text{ litres per day})$ with that of the urine released $(1.5 \text{ litres})$,suggests that nearly $99\%$ of the filtrate is reabsorbed by the renal tubules. This process is called reabsorption.
This process takes place in the various parts of the uriniferous tubules. For example,substances like glucose,amino acids,and $Na^{+}$ in the filtrate are reabsorbed actively,whereas nitrogenous wastes are absorbed by passive transport in the $PCT$.
Filtrate flowing away from the $PCT$ gets concentrated in the loop of Henle. Urine is more concentrated if the length of the loop of Henle is greater.
Secretion:
This process occurs in the $DCT$ where tubular cells secrete substances like $H^{+}$,$K^{+}$,and ammonia into the filtrate. These substances are not filtered during glomerular filtration. Ammonia,uric acid,$H^{+}$ ions,and medicinal drugs like penicillin are secreted in this way.
Thus,urine is formed and transported to the collecting duct. Water is absorbed in the collecting duct,and highly concentrated urine is emptied into the renal pelvis.