Dictionary > Nematode

Nematode

Definition
noun, plural: nematodes
An unsegmented worm belonging to the phylum Nematoda; also called roundworms
Supplement
The nematodes are invertebrates belonging to phylum Nematoda. They have unsegmented thread-like body. Many of them are parasitic, living inside their host. Together with other parasitic worms such as flatworms, cestodes, and trematodes, the nematodes belong to a group of helminths. The nematodes are distinguished from other helminths by their thread-like unsegmented body, tough outer cuticle, and the presence of a tubular digestive system with openings at both ends.
Many of the species are disease-causing. The infection of the nematode Ascaris lumbricoides is characterised by an early pulmonary phase related to larval migration and a later, prolonged intestinal phase. Adult worms are 15-40 cm in length and maintain themselves in the lumen of the small intestine. Infection occurs after ingesting eggs contained in contaminated food or more commonly, by transmission to the mouth by the hands after contact with contaminated soil. Treatment is with mebendazole or pyrantel pamoate. Other parasitic nematodes include filarias, hookworms, pinworms, and whipworms.
Free-living species feed on algae, fungi, fecal matter, dead organisms, etc. An example of a free-living nematode is Caenorhabditis elegans that lives in the soil.
Word origin: Greek nema, nematos (“thread”)
Also called:

  • roundworm

See also:

  • helminth
  • filarial
  • hookworm
  • ascarid
  • pinworm
  • whipworm


    You will also like...

    Protein (illustration)
    Protein Variety

    The sequence of amino acids determines the type of protein. Protein is synthesized according to the sequence of nucleoti..

    green plant cells
    Plant Cells vs. Animal Cells

    Plant cells have plastids essential in photosynthesis. They also have an additional layer called cell wall on their cell..

    Endemic Flora of New Zealand
    New Zealand’s Unique Flora

    If New Zealand has lots of unique animals, it's also got a whole lot of unique plants. Find out more about some of them,..

    Adaptive Radiation
    Adaptive Radiation

    The diversification of several new species from a recent ancestral source, each adapted to utilize or occupy a vacant ad..

    Young plant growing from the soil.
    Soils

    Nutrients in the soil are essential to the proper growth of a land plant. This tutorial deals with the properties of soi..

    Still Water Community Plants
    Still Water Community Plants

    This tutorial looks at the adaptations of freshwater plants for them to thrive in still water habitats. Familiarize your..