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Unlike the flatworms, nematodes have a tubular digestive system, with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. [3]
For example, the word stylet or stomatostyle is used for the primitive piercing mouthparts of some nematodes [1] and some nemerteans. In these groups the stylet is a hardened protrusible opening to the stomach. These stylets are adapted for the piercing of cell walls and usually function by providing the operative organism with access to the ...
Whole blood with microfilaria worm, giemsa stain. L. loa worms have a simple structure consisting of a head (which lacks lips), a body, and a blunt tail. The outer body of the worm is composed of a cuticle with three main layers made up of collagen and other compounds which aid in protecting the nematodes while they are inside the digestive system of their host.
For example, the word stylet or stomatostyle is used for the primitive piercing mouthparts of some nematodes [1] and some nemerteans. In these groups the stylet is a hardened protrusible opening to the stomach. These stylets are adapted for the piercing of cell walls and usually function by providing the operative organism with access to the ...
Specializing occurs when the digestive tract or alimentary canal has a separate mouth and anus so that transport of food is one-way. The most primitive digestive tract is seen in nematodes (phylum Nematode), where it is simply a tubular gut lined by an epithelial membrane. Earthworms (phylum Annelids) have a digestive tract specialized in ...
Trichinella is the genus of parasitic roundworms of the phylum Nematoda that cause trichinosis (also known as trichinellosis). Members of this genus are often called trichinella or trichina worms. A characteristic of Nematoda is the one-way digestive tract, with a pseudocoelom (body cavity made up of only an ectoderm and endoderm).
Once the larvae have entered the host they travel in the circulatory system to the lungs where they leave the venules and enter the alveoli. They then travel up the trachea and are coughed up, swallowed and end up in the small intestine. In the small intestine, the larvae moult into stage four (L4) the adult worm.
Mermithidae is a family of nematode worms that are endoparasites in arthropods. As early as 1877, Mermithidae was listed as one of nine subdivisions of the Nematoidea. [2] Mermithidae are confused with the horsehair worms of the phylum Nematomorpha that have a similar life history and appearance. Mermithids are parasites, mainly of arthropods ...