Search results
Results from the WOW.Com Content Network
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]
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.
The digestive system of gastropods has evolved to suit almost every kind of diet and feeding behavior. Gastropods ( snails and slugs ) as the largest taxonomic class of the mollusca are very diverse: the group includes carnivores , herbivores , scavengers , filter feeders , and even parasites .
The developing digestive tube of an embryo forms as a blind pouch called the archenteron. In protostomes , the coelom forms by a process known as schizocoely . [ 6 ] The archenteron initially forms, and the mesoderm splits into two layers: the first attaches to the body wall or ectoderm , forming the parietal layer and the second surrounds the ...
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).
The left image shows the free-swimming cercariae, the swimming "tail" is clearly visible. The right side of the diagram shows the cysts attached to grass. F. hepatica has a tegument that protects it from the enzymes of the host's digestive system, whilst still allowing water to pass through. [20]
Ascaris is a nematode genus of parasitic worms known as the "small intestinal roundworms". [1] One species, Ascaris lumbricoides , affects humans and causes the disease ascariasis . Another species, Ascaris suum , typically infects pigs .
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 ...