Describe the roll of kupffer cells in the liver

Kuppfer cells are a specialised type of macrophage. They travel within the sinusoids of the liver and breakdown and recycle old red blood cells. 

Red blood cells contain heamoglobin, and when haemoglobin is broken down it produces bilirubin. This is excreted as part of the faeces and gives it its brown colour. 

(OCR BIOLOGY A2)