Energy and Mode of Nutrition
Nematodes have a simple digestive tract that includes only a long hollow intestinal cavity that contains only muscles that run vertically down the worms body to aid in simple contraction movement. The food enters the mouth into the pharynx and continues to the anus. Here, the food is excreted back into the environment to be used by other organisms. Because worms lack a vascular system and true respiratory system, the uptake of nutrients is regulated by the excretory canal and dispersed through the body canal.
This slice of a worm’s body shows the detail of the layout
of the digestive tract and the positioning of the muscles,
nerves, and other interior organs.
Parasitic worms do not obtain their nutrients in such a communally beneficial manner, but still they are able to obtain their food and live off of the host. Worms found in the intestinal tracts of humans and animals can cause serious problems for their hosts because they absorb all the nutrients that are usually available to them and cause malnutrition, along with frequent vomiting and diarrhea. Current studies are trying to find the relation between malnutrition and infectious disease by nematodes, in order to determine which came first and which caused which.