How do our kidneys filter blood using osmosis?

The answer

The kidneys contain about one million tiny filtering units called nephrons. Blood enters each nephron under pressure, forcing water and small molecules through a semi-permeable membrane while retaining blood cells and large proteins. The filtrate then passes through a series of tubules where osmosis and active transport selectively reabsorb water, glucose, and essential ions back into the blood. About 180 liters of fluid are filtered daily, but 99% is reabsorbed - only 1 to 2 liters leave as urine.