Nematodes have a complete digestive system. Part of what makes a nematode so unique is that is has open ends on both ends of its body, which help to classify the species. The system is usually broken into three parts: the stomodeum, the intestine, and the proctoduem. The stomodeum consists of a small buccal cavity (mouth and lips) and an esophagus which are lined with a cuticle. The mouth of a nematode is shaped according to its diet (see Intraspecific), which will allow the nematode to puncture its competition with a stylet. The proctodeum, rectum, also has a cuticle lining. The movement of food through the nematode is a result of the worm moving.
The Stomodeus:
- This is the opening on a nematode, which consists of a buccal cavity, cephalic vesicle, and an esophagus.
- The buccal cavity is usually a small opening that leads directly to the esophagus. If the mouth is larger, depending on diet, this means the nematode has a prominent buccal cavity with thick walls and teeth.
- The esophagus is muscular, used to pass food into the intestine by a pumping action, necessary to pull food through.
- The esophagus is an initial screening characteristic to identify a nematode.
- Nematodes have a maximum of six lips around the mouth opening.
- Digestive glands in the esophagus produce enzymes, amylase, proteases, cellulases, chitinases, and pectinases, which start the process of breaking down food.
- Nematodes with stylets sometimes inject these enzymes into their prey.
The Intestine:
- There is no stomach, so food passes straight through from the esophagus to the intestine.
- The intestine is a straight, roughly circular, tube in between a wall of a single layer of columnar cells. The inside of these cells consist of many projecting microvilli used because of their immense absorption capacity, which absorb nutrients.
- Enzymes also help with the digestion.
- The intestine is muscleless and forms the main length of the gut. Because it is a muscleless passageway, food pushes down the food below it.
- The intestine has valves or sphincters at both ends which help control the movement of food through the body.
The Proctodeum:
- This is the last part of the digestive system. This the tube that is lined by cuticle, which forms the rectum and expels of waste through the anus, to the outside of the body.