What structure in the kidney is primarily responsible for filtering blood?

The nephron is the fundamental functional unit of the kidney responsible for filtering blood. Each nephron consists of a renal corpuscle and a renal tubule. The renal corpuscle includes the glomerulus, a network of capillaries that performs initial filtration of blood. As blood passes through the glomerulus, water, ions, and small molecules are filtered out, forming a filtrate that eventually becomes urine after further processing in the nephron's tubules.

The renal tubule, which consists of the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting ducts, plays a crucial role in reabsorbing water and essential solutes back into the bloodstream, while excreting waste products. This intricate design of the nephron allows not only for filtration but also for the regulation of important physiological processes, such as electrolyte balance and blood pressure, making it central to kidney function.

The other structures mentioned, such as the medulla and cortex, are parts of the kidney that house nephron components and play supporting roles, but they are not directly involved in the process of blood filtration. The renal pelvis serves as the funnel for urine flowing from the collecting ducts to the ureter, but it does not engage