What is the process called that the kidneys use to filter blood?

The process that the kidneys use to filter blood is known as glomerular filtration. This occurs specifically in the glomeruli, which are tiny structures within the nephron—the functional unit of the kidney. During glomerular filtration, blood pressure forces water, ions, glucose, and smaller molecules from the blood in the glomeruli into the Bowman’s capsule, creating a filtrate. This process effectively removes waste products and excess substances from the bloodstream, while allowing essential components to be reabsorbed later in the nephron.

While filtration is a broader term that encompasses various types of filtering processes, glomerular filtration specifically refers to the unique mechanism utilized by the kidneys to process blood. Osmosis and absorption describe different physiological processes unrelated to the specific filtering action that occurs in the kidneys. Osmosis is the movement of water across a semi-permeable membrane, while absorption pertains to the uptake of substances, typically in the intestines or renal tubules, not the initial filtering action carried out in the glomeruli. Thus, glomerular filtration is the most accurate and specific term to describe how the kidneys filter blood.