In the past, when the internal organs were removed from a body they were placed in hollow canopic jars.
Over many years the embalming practices changed and embalmers began returning internal organs to bodies after the organs had been dried in natron. However, solid wood or stone canopic jars were still buried with the mummy to symbolically protect the internal organs.
Imsety the human-headed god looks after the liver.
Hapy the baboon-headed god looks after the lungs
Duamutef the jackal-headed god looks after the stomach
Qebehsenuef the falcon-headed god looks after the intestines.