How does the nephron perform filtration and reabsorption

Each nephron in the kidney is a microscopic filtration unit that cleans the blood. It starts in the glomerulus, a network of capillaries where blood pressure forces water, salts, glucose, amino acids, and wastes out of the blood into a structure called Bowman’s capsule. This process, known as filtration, separates useful substances from waste. Large molecules like proteins and blood cells remain in circulation because they’re too big to pass through.

The filtered liquid, called filtrate, then moves through the renal tubule, where reabsorption occurs. Essential materials like glucose, amino acids, and most water are reabsorbed into nearby capillaries. 

The Loop of Henle helps concentrate urine by reabsorbing water and salts in a controlled manner. Later, the distal tubule and collecting duct fine-tune this process, ensuring the body keeps what it needs and expels what it doesn’t.

The remaining fluid mostly urea, extra water, and salts becomes urine, which travels to the bladder. Through this balance of filtration, reabsorption, and secretion, nephrons ensure that waste is efficiently removed while valuable nutrients and fluids stay in the bloodstream.