Answer:
The structural and functional unit of the kidney is called nephron. Nephron is made up of two parts renal corpuscles and renal tubule. The function of nephron is to filter the blood to remove waste materials from it.
Renal corpuscles
Renal corpuscles are made up of glomerulus which is a tuft of capillaries originates from incoming afferent arteriole and bowman's capsule which surrounds the glomerulus. The function of renal corpuscles is to filter blood from glomerulus and pass it to the renal tubule.
Renal tubule is made up of three parts PCT(proximal convoluted tubule), loop of Henle and DCT(distal convoluted tubule).
PCT: It is the main site of reabsorption and reabsorption of most of the ions like K⁺, Na⁺, Cl⁻and HCO₃⁻, water, glucose, and other essential molecules takes place in this section. Ions like H⁺ and NH⁴⁺ is secreted in the PCT.
Henle's loop: It contains descending and ascending loop. The descending loop is impermeable to ions but permeable to water and ascending loop is impermeable to water and permeable to ions like Na⁺,k⁺, Cl⁻. It plays the main function in urine concentration.
DCT: The main function of DCT is to maintain urine pH by reabsorbing ions like Na⁺, Cl⁻,HCO₃⁻ from it and secretion of ions like H⁺, K⁺ , and NH₄⁺ in it.