The kidneys are the primary organs that filter the blood.
How the Kidneys Filter Blood
The kidneys perform this vital function using millions of tiny filtering units called nephrons. Each nephron consists of a filter (the glomerulus) and a tubule. Blood is filtered in two steps:
- Glomerular filtration: The glomerulus filters the blood, removing waste products and excess water.
- Tubular reabsorption: The tubules reabsorb essential substances like water, glucose, and electrolytes back into the bloodstream, while further refining waste products for excretion as urine.
A normal kidney contains between 0.8 and 1.5 million nephrons, each working in parallel to efficiently filter the entire blood volume multiple times daily. A glomerular filtration rate (GFR) test measures how well your kidneys are performing this filtration process. A low GFR indicates impaired kidney function. (Source: NIDDK, MedlinePlus)
Other Blood Filtering Mechanisms
While the kidneys are the primary blood filters, other organs play supporting roles:
- Spleen: The spleen filters blood, removing old or damaged red blood cells. (Source: NIH)
- Artificial filters: Medical devices like vena cava filters can prevent blood clots from traveling to the lungs, acting as a filter in specific cases. (Source: Cleveland Clinic, Johns Hopkins Medicine, Yale Medicine)
- Extracorporeal filters: Used in medical procedures like dialysis, these artificial filters cleanse the blood outside the body. (Source: ScienceDirect)
In summary, while various organs contribute to blood purity and clot prevention, the kidneys are the main and crucial blood filters of the human body.
