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17.7: Excretion of Metabolic Waste Products

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    39273
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    Not only does blood deliver nutrients and oxygen to cells, but equally important, blood also transports metabolic waste products away from cells. The thousands of metabolic reactions taking place in your cells generate more than just energy; metabolic waste products such as water, carbon dioxide, and nitrogen-containing compounds are produced as well.

    Although the term elimination refers to the removal of solid waste (feces) from the body, the term excretion refers to the removal of metabolic waste products. The removal of solid and metabolic waste products are both vital to your health.

    The main excretory organs involved in the removal of metabolic waste products include the liver, kidneys, lungs, and skin. Collectively, these organs help prevent the accumulation of toxic waste products by aiding in their removal. For example, the liver converts ammonia— a nitrogen-containing by-product of protein breakdown—into a less toxic substance called urea, which is released into the blood. The kidneys then filter the urea out of the blood so it can be excreted from the body in urine. This is why people with impaired kidney function often undergo a treatment called dialysis. Dialysis involves a special machine that performs similar functions of healthy kidneys. Without dialysis, toxic metabolic waste products would accumulate in the blood, eventually resulting in death.1

    References

    1. McGuire, M., & Beerman, K. A. (2017). NUTR2. (2nd ed.). Cengage Learning.

    17.7: Excretion of Metabolic Waste Products is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by LibreTexts.

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