• Question: What is the difference between egestion and excretion?

    Asked by nkjones to Amy, Karen, Sarah, Vijay, Will on 14 Jun 2012.
    • Photo: Sarah Martin

      Sarah Martin answered on 14 Jun 2012:

      Hi nkjones! That’s a great question! Egestion and excretion are actually quite similar – they both are processes in which unwanted things are removed from a cell or an organism.
      The difference is that egestion gets rid of undigested food (in humans that’s poo!) while excretion gets rid of waste from chemical reactions of the body (in humans these are processed in the liver and the kidney and our excretion happens in form of urine and sweat).
      All clear?
      🙂 Sarah

    • Photo: Karen Reed

      Karen Reed answered on 15 Jun 2012:

      Hiya nkjones – I didn’t know the answer to this. Just looked it up and read Sarah’s answer and it seems egestion is getting rid of unwanted stuff using the digestive system – that is the guts so poo as sarah said, while excretion is getting rid of unwanted stuff from the blood, tissues or organs so that’s usually urine (or wee) or sweat. Great question thanks

    • Photo: Amy Birch

      Amy Birch answered on 15 Jun 2012:

      Hi nkjones,
      Excretion is the removal of unwanted metabolic products (when chemical reactions happen in the body, there are always some substances that are produced that we don’t use). This is usually done by the kidneys (urine), skin (sweat), and the lungs (carbon dioxide when we breathe out).
      Egestion is the removal of substances that we can’t use in our body (they cannot be digested or used in any chemical reactions). In humans, this is undigested food that is stored in the rectum until we go to the toilet and poo it out!

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