Nephrons, the filtering units of the kidney
Nephrons filter the blood and recycle useful components from the pre-urine.
   
A nephron starts with a rough filter called the Glomerulus.
   
Through this filter, blood plasma containing wastes, minerals and small molecules are pressed.
   
Large proteins remain in the blood, while small substances and water are pressed through the filter to form pre-urine.
   
The pre-urine flows into a tube or tubule.

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