What waste is filtered from the blood by kidneys?

The kidneys play a vital role in maintaining the body's internal environment by filtering waste products and excess fluid from the blood. The waste products that the kidneys filter include:

1. Urea: Urea is the main nitrogenous waste product of protein metabolism. It is produced when the liver breaks down proteins. Urea is transported by the blood to the kidneys, where it is filtered out and excreted in urine.

2. Creatinine: Creatinine is a waste product of muscle metabolism. It is produced when creatine, a molecule that helps muscles store energy, is broken down. Creatinine is also filtered by the kidneys and excreted in urine.

3. Uric Acid: Uric acid is a waste product of purine metabolism. Purines are compounds found in some foods, such as meat, seafood, and certain vegetables. Uric acid is filtered by the kidneys and excreted in urine. High levels of uric acid can lead to gout and kidney stones.

4. Electrolytes: Electrolytes are minerals that carry an electric charge. They are essential for many bodily functions, such as regulating fluid balance, muscle contractions, and nerve function. The kidneys help to regulate the levels of electrolytes in the blood by filtering out excess amounts.

5. Toxins: The kidneys also help to remove toxins from the body, such as drugs, heavy metals, and environmental pollutants. These toxins are filtered out of the blood and excreted in urine.

In addition to these waste products, the kidneys also filter out excess water to produce urine. The amount of urine produced varies depending on factors such as fluid intake, activity level, and environmental conditions.