Any material entity that is located in the digestive tract. This includes undigested food and liquid as well as unexcreted waste products. It also includes other entities such as ingested stones used to aid digestion. Any microbial cells or cell populations are also included.
mesoderm-derived structure +
morphological feature +
multi cell part structure +
multicellular anatomical structure +
muscle spindle +
muscle structure +
myelin
regenerating anatomical structure +
reticuloendothelial system +
retroauricular region
sac +
septum +
sex-specific anatomical structure +
skeletal musculature +
structure with developmental contribution from neural crest +