The nephron is the structural and functional unit of the kidney, with approximately 1.3 million nephrons per kidney that cannot regenerate. Nephrons consist of a renal corpuscle, which includes the glomerulus and Bowman's capsule, and renal tubules, with various segments for different functions. There are two main types of nephrons: cortical nephrons, which constitute 85% of the total and are located in the outer cortex, and juxtamedullary nephrons, which are deeper and play a critical role in urine concentration.